APR GTI MK4 Cat Back Exhaust w/High-Flow Turbo-Back w/Custom Down Pipes Review

VW Golf GTI is the bench for hot hatches. I grew up around Volkswagen Golf’s since I was a little kid. My uncle had an MK1 VW Golf back in the day, and I’ve owned two GTI’s. My first car was an MK3 2.8L VR6 GTI, while my second car is an MK4 1.8 Turbo 4 cylinder GTI. Both VW’s were equipped with a proper manual transmissions.

These cars have always been amazing all around cars that offered lots of room and peppy performance for the size. Over the years the golf has gained power (and weight) by adding GTI Models that were initially powered with naturally aspirated VR6 engines ranging from 2.8L N/A engines, all the way up to the infamous R32, and now with the Golf R. But somewhere in between that time, VW decided to fit the MK4 with a 1.8L turbo charged four-cylinder engine that is shared with other VW and Audi Models in the USA, Skoda and Seat in the Europe.

2003 2004 2002 APR TUNED Cat Back MKIV MK4 Golf GTI 1.8T Nuespeed, Turbo-Back and Custom Downpipes.

Car Maker: VW
Year: 2003 (1997-2004)
Model: Golf GTI
Engine: 1.8 T/ 20v
Transmission: 5 speed manual
Body Style: Coupe
Exhaust Modification Type: Custom made turbo-back exhaust
Purchased/Made: purchased

The GTI gained power as well as weight over the years. The 1.8T engine provided adequate power low in the rev range torque.

My MK4 Volkswagen GTI was all stock when I purchase it. I immediately started looking to get the most out of the 1.8T by purchasing some aftermarket goodies. The first thing I did was installed an aftermarket cold intake system, a sequential blow off valve, a turbo timer, digital turbo boost gauge.

These small mods added another dimension to the driving experience of my 1.8T MK4 VW GTI. The “swoosh” sound of the BOV made it sound awesome. But there was still something missing from the equation. The car’s exhaust sound was too quiet, while the sequential BOV was super loud between gear changes. That was enough for me to rush my decision to install a custom-made turbo back exhaust on the GTI.

After snooping around a few VW online communities and talking to VW Tuning shops around town, and learning how to get most out of the 1.8T in the GTI. I decided to go with a high flow cat, and add an O2 sensor spacer after the catalyst to eliminate the CEL (Check Engine Light) from coming on. As for the muffler, I decided to purchase an APR Tuned Stainless Steel 2.5 Inch Catback Exhaust sport muffler from a local Revo tuning shop. (Since then, I was able to find a better deal online)

I live close to an industrial area where several custom steel fabrication shops as well as a few very talented auto mechanics do business.

With the help of my dad’s friend that happens to have a side business tuning late-model Audi’s and VW’s, we took out the downpipes. Cut off the stock cat, retained all the stock piping, with a bit of massaging work and welding skills, we welded on the aftermarket universal high-flow cat. Kept all of the original flanges and connecting positions to the Turbo and to the cat back.

2003 2004 2002 APR TUNED Cat Back MKIV MK4 Golf GTI 1.8T Nuespeed, Turbo-Back and Custom Downpipes.

On the back-end, it was a simple bolt on installation of the aftermarket APR Tuned Stainless Steel 2.5 Inch cat back Exhaust. My GTI has an aftermarket rear bumper lip/valence that I wanted to keep intact without cutting. I purchased the tip-less APR cat back exhaust to clear my aftermarket lip… So we welded up some custom round dual chrome tips. The hangers went directly into place, while the exhaust tips lined up great with the bumper, as you can see from the pictures.

The whole operation of deleting the cat, installing a high flow cat, putting on an oxygen sensor spacer (aft of the cat), installing the tip-less APR tuned 2.5” cat back exhaust, then welding on dual tips took us around 3 hours to complete.

Driving Impressions:
There is no time to waste after installing the exhaust on the MK4 1.8T GTI. It was time to take the car out for a test drive. When I first turned on the ignition, the car came to life. It was as if the car was resurrected from the dead. It sounded deeper, stronger, and way sportier than it ever was with the stock cats and muffler. To sum it all up, it was just how I wanted my GTI to sound.

The GTI didn’t show any signs of low-end back pressure loss, at least not any that I could pickup from driving around town. Actually it felt like there was an overall increase of torque on the full rev range. The new custom exhaust setup clearly freed up the flow of exhaust gases as compared to the restricted stock 1.8T GTI setup.

At this point even your passenger will hear, and most importantly, will feel the difference in acceleration with the new exhaust. I’ve gotten a few complements from my buddies on how quick the car accelerates. The trick now is maintaining front wheel traction with the added torque and weight loss at launch. But with stickier tires, I was able to walk my friend’s 2009 TSI 2.0T GTI with 6 speed manual transmission a few times. Maybe that will change soon after he installs a performance exhaust and stage 2 APR tune.

The most rewarding aspect of this mod is dropping down from high to low gears. The sound it makes is like a rally car. Driving this car with the new custom made exhaust is awesome; u can feel that the car has changed. The sound is pure and brutal at the same time, but still refined in a way that won’t bother or irritate any passengers that are riding along because it’s not loud inside the cabin.

Parking at work is in an underground parking structure. When I pull into the parking structure, and make my way down to the 3rd floor below street level, my colleagues know right away when I arrive at work due to the unique sound coming out of the dual exhaust tips on my GTI.

2003 2004 2002 APR TUNED Cat Back MKIV MK4 Golf GTI 1.8T Nuespeed, Turbo-Back and Custom Downpipes.

Additional Information:
The build quality of APR exhaust is very impressive. It is well worth the money, even though there are cheaper alternatives. If you’re going to install an aftermarket exhaust on your GTI, make sure you do it right from the get go. If I had to do it over again, I would’ve purchased bolt on APR downpipes and high flow cats instead of spending 3 hours on fabricating of the universal high flow cats to fit with my stock system.

Available Cat-back Exhaust Systems for the MKIV 1.8T Golf and Golf GTI 1.8T:

APR Tuned Stainless Steel 2.5 inch Catback Exhaust:

    • GTI 337 & 20th Ann. 02-03
    • VW Golf 1.8T 00-02
    • VW Golf 1.8T 03-05

APR Tuned Stainless Steel 3 inch Catback Exhaust:

    • Volkswagen Golf 1.8T 03-05
    • Volkswagen Golf 1.8T 03-05
    • Volkswagen GTI 337 & 20th Ann. 02-03

Milltek Cat-Back Exhaust 2.5 and 3.0 inch:

    • Volkswagen Golf 1.8T 98-04
    • R32 Style Volkswagen Golf 1.8T 98-04

Neuspeed 60mm (2.4 inch) Catback Exhaust

    • w/DST Tip Volkswagen Golf IV 1.8T, VR6 2002.5+
    • w/SST Tip Volkswagen Golf IV 337 1.8T 02+

B&B 2.5 inch Catback Exhaust System:

    • w/Twin Tips Volkswagen Golf GTI 03-05
    • w/o Tips Volkswagen Golf GTI 00-02
    • w/ Downpipe w/o Tips Volkswagen Golf GTI 00-02
    • w/ Downpipe w/Single Tip Volkswagen GTI 337 03-05
    • w/ Downpipe 2.5 inch w/Twin Tips Volkswagen Golf GTI 03-05
    • w/ 2.5 inch Single Tip Volkswagen GTI 337 03-05

B&B 3 inch Catback Exhaust System:

    • w/Twin Tips Volkswagen Golf GTI 03-05
    • w/ Downpipe w/Twin Tips Volkswagen Golf GTI 03-05
    • w/ Downpipe With 3 inch Single Tip Volkswagen GTI 337 03-05
    • w/ 3 inch Single Tip Volkswagen GTI 337 03-05

Megan Racing Cat Back Exhaust 2.5 inch:

    • Volkswagen Golf 03-05
    • Volkswagen Golf 99-02
    • Volkswagen GTI 20th Anniversary 03


Big thanks to Omar H. for sharing his experience with the CarExhaustReviews community. Enthusiasts will be able to benefit from this experience down the line.

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