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Vauxhall Astra J Best Mods & Upgrades

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Table of Contents


Produced from late 2009, the Astra J is the 6th generation of the well-established Astra range that saw its origins in the early 1980s.

The Astra J was offered in various body styles, including a 5-door hatchback, Sports Tourer (estate), and GTC (3 door coupé). Throughout its lifespan, the model came with an extensive range of petrol and diesel engines.

Petrol engine options ranged from a 1.4L naturally aspirated unit to a robust 2.0L turbocharged engine. 

Diesel options encompassed 1.3L, 1.7L, and 2..0L CDTI engines, delivering a broad selection of performance capabilities to meet the preferences of individual customers.

Regardless of what engine or specification your Astra J has, we’ll go over all the best modifications and upgrades for your car to boost it’s looks, driveability and performance!

Lowering Springs

Undeniably, the first reason many car enthusiasts consider adding lowering springs to their Astra J relates to the aesthetic charm it gives the car.

Lowering springs reduce the gap between the tyre and the wheel arch, giving your Astra J a more assertive and sportier look. It makes the car appear more streamlined and sleek.

In addition to aesthetic enhancements, lowering springs significantly contribute to improved handling performance.

A lowered car reduces the centre of gravity which improves handling, balance, and grip. This modification enables you to corner more swiftly and confidently.

As the distance from the centre of gravity to the ground gets minimised, it also results in less body roll or leaning during cornering.

When choosing lowering springs, make sure to go with a reputable brand such as Eibach or H&R.

Common drop heights are normally between 20m-30mm depending on the model although you can also get a 40mm kit from Eibach.

It’s important to remember going too low can have detrimental effects. Aside from lack of ground clearance and speed bumps, it will also put more stress on the standard shocks.

Eibach lowering springs for the Astra J

Eibach 40mm Lowering Springs

For the Astra J


Looking to increase the performance of your Astra J?

A remap is often the most suggested upgrade, and with good reason. A remap is one of the best valued performance upgrades you can do to your Astra.

Well, for most models anyway. 

The naturally aspirated engine variants won’t respond as well to a remap but the turbocharged engines can show some impressive power gains from a remap alone.

Let’s take a quick look at some expected power figures from a remap on a couple of different models.

Taking a look at the 1.7 CTDI variant producing 128bhp from the factory, you can achieve power gains of 35bhp-40bhp from a remap alone.

On the petrol front, the 1.6 turbo variant producing 177bhp from the factory can get a lovely 35bhp increase from a remap.

There are various other engine configuration with varying power outputs in standard form so the remap gains will vary slightly.

It’s also worth noting that if you have a performance exhaust fitted or any other performance mods then you can expect even more gains from a remap! Just make sure to have the physical mods fitted to the car first.

Rear Spoiler

A rear spoiler extension assists in managing the airflow around the car, reducing drag and increasing fuel efficiency. It functions by redirecting the ‘spoiled’ turbulent air over the rear end, leading to less resistance and offering better high-speed stability.

While the aero effects of adding a rear spoiler will be minimal, the visual effects aren’t!

There are a variety of aftermarket rear spoilers for the Astra J to choose from. Most simply slot over the original mini spoiler tend to be quite a subtle modification. 

Even as a subtle touch, they make a big difference in making the rear end look sportier and streamlined. 

You can also get an aftermarket spoiler like the ones that comes as standard on the Astra J VXR.

The majority of the rear spoilers are relatively cheap and easy to install. Adhesive is the most common method of applying them to the car and as such you shouldn’t need to drill or hack up the rear of your Astra to get it mounted.

Many of the aftermarket spoilers come in black or unpainted so you may want to have them painted to the colour of the car for an OEM look or maybe left in black to create some contrast. 

There are various options on eBay like the one below for the 5 door Astra J that replicates the VXR styled spoiler. 

VXR Styled Spoiler

For the Astra J


Let’s take a look at another subtle aero mod – sideskirts!

The sporty, refined aesthetic these fittings bring project a dynamic silhouette, embodying a sleeker and more assertive stance on the road.

Sideskirts visually lower the Astra’s profile, creating an impression of a grounded stance, which could be ideal for those looking to emphasize a performance-oriented image.

They also have the ability to help reduce drag although as with the rear spoiler this won’t be noticeable in the vast majority of driving situations. 

You can purchase sideskirts for the Astra J at the bottom of this section.

Like most universal styled sideskirts, they may require a little bit of trimming to get the perfect fitment. 

Made out of ABS, they are a lot more impact resistant and resilient as opposed to many fibreglass counterparts. 

Sideskirts for the Astra J


For the Astra J

Interior Mods

When we think of car modifications, many of us picture performance upgrades and flashy exterior mods.

While these are great, they typically involve higher costs and can be complex to install.

But what if there was a more affordable and simpler way to start your car modification journey without causing a significant dent in your wallet?

Welcome to the world of interior car modifications!

The interior of a car often gets overlooked when we think about modifications. Yet, it’s where we spend most of our time while driving.

There are loads of great and subtle ways you can improve the interior, whether it be for aesthetics or improving your driving experience.

Mods include:

A lot of the above mods are inexpensive compared to traditional exterior and performance mods, and their ease of install means you should be able to install a lot yourself saving you money on mechanic labour costs. 

Performance Exhaust

An aftermarket exhaust system on your Astra J is a great way to unlock some extra power and give your car a sporty exhaust tone. 

A well-made aftermarket exhaust system enables a deeper and better-rounded tone, producing a true performance sound. With each rev of the engine, there’s a gratifying, throaty rumble that standard exhausts can’t provide.

Besides the captivating tones, an aftermarket exhaust can also boost the performance of your Astra.

Aftermarket exhaust systems have less restriction and greater pipe diameter, which promotes efficient exit of exhaust gases from the combustion chamber. This drop in back pressure triggers an increase in horsepower and torque.

There are various options for aftermarket exhausts depending on what model of Astra J you have.

Generally speaking, the petrol variants will respond better to the performance increase and sound enhancements due to them revving higher. 

If you can’t find an off-the-shelf exhaust for your particular model then you can always have one fabricated at a local exhaust shop which means they can also customise it to your liking in terms of the sound it produces. 

The VXR variants sound particularly nice with an aftermarket exhaust. Scorpion do a lovely sounding non resonated cat-back exhaust system for the Astra J VXR which you can check out below.

Scorpion Non Resonated Catback

For the Astra J VXR

Wheel Spacers

Wheel spacers are a popular mod among car enthusiasts due to their simplicity and affordability. 

Adding wheel spacers essentially pushes the wheels out.

This create a wider track and give the Astra a sportier, more grounded look. This not only makes your car more visually compelling but also allows for a more aggressive stance.

If you are planning fitting a set of aftermarket wheels, then wheel spacers to be necessary for correct fitment. 

Aftermarket wheels often have different offsets that might not align perfectly with the Astra’s hub. In such cases, wheel spacers can be required to ensure a perfect fit along with preventing rubbing or clearance issues with brake components. 

The size of wheel spacers you go for will depend on what wheels you have and if your Astra is lowered. If it’s lowered significantly then spacers can cause rubbing issues under hard cornering. 

On a standard Astra J, 20mm is a common size of wheel spacer to bring the wheels flush in line with the body. 

20mm Wheel Spacers

For the Astra J

Stiffer Rear Anti-roll Bar

If you’re looking for a simple and effective modification to transform the handling of the Astra, then look no further than a stiffer rear anti-roll bar. 

A stiffer anti-roll bar does what it says on the tin – it helps reduce body roll!

Having a stiffer anti-roll bar on the rear on a front wheel drive car like the Astra is very handy due to is ability to reduce understeer. 

If you track your Astra or drive hard then you will be all too familiar with understeer under hard cornering which can become very frustrating. 

A stiffer anti-roll bar on the rear combats this and helps maintain balance more efficiently during cornering. 

The only model that some owners don’t bother fitting a stiffer rear anti-roll bar to is the VXR variant, due to the stiffness of the suspension that comes with it as standard. 

When it comes to anti-roll bars, you can’t go wrong with Whiteline who are one of the leading manufacturers for aftermarket roll bars for numerous cars and brands. 

They do a 3 point adjustable rear anti-roll bar for the Astra J which you can take a look at below.

Whiteline anti roll bar for the Astra J

Whiteline Anti-Roll Bar

For the Astra J

Finishing Thoughts

Regardless of what version of the Astra J you have, there are a variety of cosmetic and performance mods and upgrades out there. 

Which options you decide to go for will depend on the model you have, your budget and your goals. 

For example, it’s less costly to extract more power from the GTC and VXR models than it is from the 1.4L naturally aspirated model. If you’re the owner of the 1.4, you may wish to instead focus on cosmetic modifications and maybe fit an exhaust instead of spending large money chasing small power gains. 

Having a clear plan of what you want from your car can save you a lot of money down the line. 

Happy modding!