ZZP GXP Downpipe

Exhaust - ZZP GXP Downpipe

ZZP GXP Downpipe

44 reviews
Regular price $294.99
  • In stock, ready to ship
  • Inventory on the way

Stock downpipes are double-walled tubing with an inside diameter of just over two inches. Gains of over 10HP have been seen along with a substantial drop in knock. This part can typically be installed in under an hour.

Our downpipes are made from high quality stainless steel. Even the flanges are stainless, which isn't something any other company offers. This ensures a lifetime of rust-free operation and eliminates the need for paint that could flake off. Stainless costs a little more but we feel it's worth it. All welds are held to the strictest of quality control standards to ensure a professional finish. Our weld quality is higher than any other downpipe manufacturer. When shopping around, ask if the downpipe is 100% stainless, and ask for a close up shot of their welds. Compare them to ZZP's downpipes, and it will be apparent why ZZP's downpipes are leaps and bounds ahead of the competition.

Exit option: The default, or stock, downpipe exit will come with a 2.5" flange. This is the stock size and will allow you to bolt it in with the stock exhaust, or any aftermarket 2.5" catback. If you have a 3" catback, or are planning on purchasing a 3" catback, you will want the 3" exit option. The 3" option will not fit with the stock exhaust. 

Bolt in with cat downpipes can be used on stock to highly modified cars. We use Magnaflow, high flowing catalytic converters. They bolt into a stock or aftermarket cat back exhaust system. They include an O2 bung for the rear factory O2 sensor. 

Interlock flex (sometimes called turbo flex) is the best flex money can buy. Typically, the downpipes in our market use a single wall flex. This is durable but has a ribbed inside design that can disrupt airflow. This type of single wall flex is what people are running when you hear them complain about a whistling or ticking noise coming from their exhaust section. To remedy these issues, you can buy a double braided flex which has braided stainless on the inside, as well as outside, of the flex. The problem is that they fail very easy on supercharged cars. Interlock flex is the 3rd solution and while is costs more, it is the best. It withstands the higher temperatures of boosted applications and provides a flat smooth surface for the exhaust gas to run over. 

Please use factory torque specs when installing our downpipes.

Fits 5.3L Impala SS, Monte Carlo SS, and Grand Prix GXP. Does not fit Bonneville GXP. 

Shipping charges are based on dimensional weight.

Our downpipes come with a high flow catalytic converter that is 48 state legal. Our catalytic converters will not pass California or New York state emissions. Please contact customerservice@zzperformance.com if you have any questions.

We are currently offering $100 in store credit to purchase your stock catalytic converter back from you. If you're interested, take a photo of your stock downpipe and email it to Henry@zzperformance.com. We will provide prepaid shipping labels for domestic (U.S.) shipments.

Customer Reviews
4.8 Based on 44 Reviews
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George H.
United States United States

08 GXP downpipe

Very nice product. Excellent finish. Slight fitment issue with bolting to factory cat back. Easily revolved. Sounds a little deeper and has more tone even with the stock rear exhaust. Better throttle response even in normal driving. A worthwhile upgrade IMO. I installed it by itself to see if I noticed a difference (I did) before adding an air intake and rear mufflers.

Jacob R.
United States United States


Ordered my downpipe online & was ready a couple of hours later. Great product, can’t wait to install it. Will be buying more products from them for the build.

Brian B.
United States United States

GXP Downpipe

Very nice looking unit. The hole spread on the manifold end was off a little bit… don’t know if the studs coming out of the manifold had splayed out or the hole locations were off. Opened the holes by 1/16” and was able to get it on. Stock GXP with CAI, Magna Flow Cat-back exhaust and this downpipe improved my ET by .05 and increased my trap speed by 1 mph… I’d say it was worth it!

Frank F.
United States United States

Good but throwing p0420 code

Looks great sounds great but I didn’t originally have a catalyst code until after I installed the new Dow pipe and cat back exhaust all zzp very quiet with resonator. Maybe I have a leak if so that’s on me and I need to pass emissions for illinois

ZZPerformance ZZP GXP Downpipe Review
Tony L.
United States United States

Zzp gxp downpipe

I love it easy to install compliments my magna flow catback. Notice better bottom end

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