The 7 Best VW Mk4 Jetta GLI Mods & Performance Upgrades

The Volkswagen Mk4 Jetta GLI is one of the most popular vehicles around for modifying and tuning- and for good reason. Its already quick right off the lot, it looks great, has ample room for storage and passengers. Whether you're looking to make your daily driver a bit quicker, or to turn your GLI into a full blown race car, UroTuning has the parts and the knowledge to help you get where you need to be with your build!

MOD #1

Deciding which Mk4 Jetta GLI upgrades to prioritize can be difficult. To get the most bang for your buck, start with a performance engine tune. Engine control unit (ECU) software will increase your Mk4 GLI's horsepower by modifying boost, fueling, ignition maps, and more. The dollar per HP gain is unmatched by any other Mk4 GLI power mods you could make to your engine. In addition to the engine, there are also tunes for your transmission. Automatic or Dual Clutch equipped cars can benefit from a Transmission Control Unit (TCU) tune to deliver increased power, higher RPM limit, faster shifts, optimized shift points, adjustable launch control, and additional transmission performance. Here are some of the top brands we'd recommend for Mk4 GLI power mods and tunes:

MOD #2

Your engine is essentially an air pump, so the more air you pump, the more power it will make! The intake system is heavily restricted from the factory to keep things quiet and optimized for low-end torque. Upgrading to a performance cold air intake will allow your engine to ingest more cold air, which will add better throttle response, sound great, and add some extra horsepower to your modded Mk4 Jetta GLI.

MOD #3

Mk4 GLI upgrades for your exhaust system can unleash the full power of your engine. Aftermarket exhaust systems and upgrades provide a quicker, more efficient route for the exhaust gasses in your engine to escape, allowing the engine to breathe easier and make more horsepower. Because of fewer restrictions and better flow, the sweet sounds that a performance exhaust creates are a big reason you want to upgrade your Mk4 GLI exhaust system.

MOD #4

If you’re ready to unleash more power in your modded Mk4 Jetta GLI, then it’s time to upgrade your downpipe. This easy Mk4 GLI upgrade is a huge way to increase your engine’s horsepower. Reducing restriction and increasing airflow right after the turbo allows for significant power gains compared to the factory downpipe. Not only will power gains be plentiful you will also net some quite nice sound when upgrading the downpipe. It's a win-win for sure!

MOD #5

To achieve that lowered stance, there are three options among the best Mk4 GLI mods for suspension systems on the market today: lowering springs, coilovers, or an Air Ride System.

1. Lowering Springs

Lowering springs are generally going to give you a more subtle drop. With springs, no adjustments can be made (unless you go with some Adjustable Lowering Springs).

2. Coilovers

If you want to dial it in or adjust it fully just how you want, then adjustable Coilovers may be the best fit for you.

3. Air Ride System

Want to lay frame at the show but also want to be able to get over speed bumps without problems? Then go all in on a complete Air Ride System. Full-ride height adjustability at the press of a button! Your budget will ultimately decide which path you take, but lowering is among the best mods for the Mk4 Jetta GLI!

MOD #6

Wheels can change the entire look of your car in an instant. At UroTuning, we firmly believe in getting new wheels after you lower your car. It’s practically an unwritten law!

Upgrading your Mk4 GLI wheels gives you that curb appeal and the extra detail that proves you aren’t just another stock car on the road. Many options and price points for Mk4 GLI wheels are available, so choose wisely.

MOD #7

Let's face it - when modding your Mk4 GLI, the first thought is always more power! But you can't forget that with all that extra GO, you also need some extra SLOW. OEM pads are a good choice, but there are better options among our selection of Mk4 GLI upgrades!

UroTuning recommends, at minimum, a good set of Ceramic Brake Pads. These pads will shed less dust and have more bite for better stopping power. For even faster stops, upgrade rotors to slotted or drilled units. Want to go all in on stopping for your modded Mk4 GLI? A Big Brake kit will give you the best braking setup and look good simultaneously!