GMPP - Missing Performance Exhaust?

back_336 · March 26, 2024

Last year I purchased a 2021 Sierra Denali Ultimate from a dealer in my area. This is my first GMC truck. Part of the reason I went with this truck was because it included the GMPP on the window sticker. When I went to see the truck I was really happy with the low mileage and how clean it was. I popped the hood to see the CAI. All good. The truck sounded a bit quiet, but not being too familiar with Sierras I just thought the GM performance exhaust was quieter than I was expecting. Anyways, fast-forward to this year as I am researching other cat back systems, and it has become pretty clear to me that I have a stock exhaust. Besides being very quiet, it has the resonators near the exhaust tips just like every other stock system I've seen.

Was there some kind of dealer shady business going on? Or possibly a shortage/backorder of the cat back system in 2021? I am more just curious at this point. The dealer I bought this truck from was not the dealer who took delivery when the truck was new.

Note: Every other "dealer installed" accessory was included as on the window sticker (CAI, Protection Package, console vault, tailgate step lights)

Other than this issue, I absolutely love the truck!

KARNUT · March 26, 2024

12 minutes ago, back_336 said:

Last year I purchased a 2021 Sierra Denali Ultimate from a dealer in my area. This is my first GMC truck. Part of the reason I went with this truck was because it included the GMPP on the window sticker. When I went to see the truck I was really happy with the low mileage and how clean it was. I popped the hood to see the CAI. All good. The truck sounded a bit quiet, but not being too familiar with Sierras I just thought the GM performance exhaust was quieter than I was expecting. Anyways, fast-forward to this year as I am researching other cat back systems, and it has become pretty clear to me that I have a stock exhaust. Besides being very quiet, it has the resonators near the exhaust tips just like every other stock system I've seen.

Was there some kind of dealer shady business going on? Or possibly a shortage/backorder of the cat back system in 2021? I am more just curious at this point. The dealer I bought this truck from was not the dealer who took delivery when the truck was new.

Note: Every other "dealer installed" accessory was included as on the window sticker (CAI, Protection Package, console vault, tailgate step lights)

Other than this issue, I absolutely love the truck!

Not too long ago a person posted for sale performance exhaust that came with his truck that he didn’t want installed even though it came with the truck. Perhaps that’s what happened with yours.

Glava2876 · March 26, 2024

I have it on my 2020. The dealer added it after I had it for a while and it is not extremely loud, but got a little louder with time. The resonators and all were still on the performance exhaust, the biggest visual difference is that it is 3” diameter.

newdude · March 26, 2024

1 hour ago, back_336 said:

Last year I purchased a 2021 Sierra Denali Ultimate from a dealer in my area. This is my first GMC truck. Part of the reason I went with this truck was because it included the GMPP on the window sticker. When I went to see the truck I was really happy with the low mileage and how clean it was. I popped the hood to see the CAI. All good. The truck sounded a bit quiet, but not being too familiar with Sierras I just thought the GM performance exhaust was quieter than I was expecting. Anyways, fast-forward to this year as I am researching other cat back systems, and it has become pretty clear to me that I have a stock exhaust. Besides being very quiet, it has the resonators near the exhaust tips just like every other stock system I've seen.

Was there some kind of dealer shady business going on? Or possibly a shortage/backorder of the cat back system in 2021? I am more just curious at this point. The dealer I bought this truck from was not the dealer who took delivery when the truck was new.

Note: Every other "dealer installed" accessory was included as on the window sticker (CAI, Protection Package, console vault, tailgate step lights)

Other than this issue, I absolutely love the truck!

Original owner may have opted to not have it installed possibly.

Factory ordered options like the intake, exhaust, mud flaps, etc. that are ordered during the build of the vehicle are all dealer installed. It could be that say the dealer ordered the intake/exhaust LPO package and the person buying the truck knew this and didn't want the exhaust installed. So the first owner would have gotten the exhaust with the truck unless the dealer worked out some sort of credit for them to buy it back.

Edited March 26, 2024 by newdude

ember1205 · April 1, 2024

Isn't GMPP on the sticker indicative of the FACTORY performance exhaust which is integrated into the Infotainment system for settings and is tied to drive modes? I know on the Camaro, there are two very different "performance" options... One is NPP which factory installed and referred to as Performance Exhaust and the dealer option of "GM Performance" exhaust. It's confusing because (as GM likes to do) they use either identical or very similar names for different things.

newdude · April 1, 2024

8 minutes ago, ember1205 said:

Isn't GMPP on the sticker indicative of the FACTORY performance exhaust which is integrated into the Infotainment system for settings and is tied to drive modes? I know on the Camaro, there are two very different "performance" options... One is NPP which factory installed and referred to as Performance Exhaust and the dealer option of "GM Performance" exhaust. It's confusing because (as GM likes to do) they use either identical or very similar names for different things.

Not on a 2021 it won't be.

NPP hit the 1500s for 2024 on 6.2s. OP's truck would have had RPO code WBC which is the dealer installed factory performance catback exhaust (the GM branded one not the Borla branded system).

What adds to the confusion is people still using the GMPP acronym. Nothing is branded with it anymore.

Edited April 1, 2024 by newdude