Good day,

You all have provided me with ample number of options with respect to modding my 04 GTP CompG and I think I have learned lots, but still need some help with my final decision. I have narrowed down my mod choices to the following and all keeping my stock exhaust beind the cat.

Option 1
ZZP 3" downpipe with hi-flow cat
3.6 pulley
Custom Tune
* possibly in the future - headers

Pros - easy install with some gains in hp, less complexity, less chance of problems
Cons - does not resolve the most restrictive portion of the exhaust

or

Option2
ZZP headers with modified trans dipstick (how many hours would this take a shop?)
3" downpipe with hi-flow cat
Custom Tune
* possibly in the future - 3.6 pulley

Pros - more gains in hp, resolves the most restrictive part of the exhaust
Cons - more complex, more changes for leaks and problems and much more cost

I would get the headers installed at a local shop and my dilema is that I cannot find anyone locally with much experience with 3800 engines, so I would go with a shop that has LS1 experience. I am hesitant about the potential cost of the install if things do not go right (and they never do go smooth the first time...right?

Anyway, this is where I am at and I am torn between the two and want to make a decision soon and need advice. What I do not understand is the cost benefit ratio between the two options listed above. How much true hp would be gained? and is it worth the extra money.

Thanks for you help and once I make this decision I will quit bugging you all

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2009 G8 GT -Sport and Premium Pkgs, Roto-Fab CAI, Cortex 93 Octane Tune, Billet Prototype Catch Can, BMR Front and Rear Sways, BMR RTAs, BMR Rear Cradle Bushings, BMR Steering Rack Bushing, GXP SW......and much more to come.

installing headers is not that hard. just take your time and follow the instructions. there are a lot of good write ups. a shop will rape you on install. check your local forum and bribe someone with beer and BBQ.

I would honestly skip the DP and go straight to the headers. I love ZZP but for the price of a DP gets you half way to headers off eBay

Do headers and do them yourself. I did my first set of headers back around april and everything came out just fine. Sure it seems hard and can seem scary but just read up a little and dive in.

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GPDIY - For All Your DIY Needs
VS CAM|3.4|HEADERS|FWI|42.5#|HPT|6000k LOWS|8000k FOGS|

Thanks guys!

Does anyone know how much hp would be gained from either option? .......roughly speaking of course!

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2009 G8 GT -Sport and Premium Pkgs, Roto-Fab CAI, Cortex 93 Octane Tune, Billet Prototype Catch Can, BMR Front and Rear Sways, BMR RTAs, BMR Rear Cradle Bushings, BMR Steering Rack Bushing, GXP SW......and much more to come.

What kind of headers did you install?

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2005 GTP
Planned Mods:
1) Wizair CAI
2) TOG Headers
3) 3-inch DP
4) 3.6 SC Pully
4a) Pro Dyno Tune
In that order. 4 & 4a done the same day.

Pacesetters. I also taught myself how to install a cam after reading through info for about a month.

_________________

GPDIY - For All Your DIY Needs
VS CAM|3.4|HEADERS|FWI|42.5#|HPT|6000k LOWS|8000k FOGS|

I have ZZP's newest Plog and 3" catless DP on my car, when I installed the DP after running a 3.6" pulley for abit I noticed a huge drop in my low end torque. The car takes off decently but lost its OOMPH it had before. I have been told headers don't cause that as badly. I'm actually looking to switch to headers next spring.


And as for the 'Diving in' to an install; I installed my 1.9 roller rockers and 105 springs myself with 0 previous experience. There are write ups everywhere to do anything pretty much, theres alot of people here willing to help you with damn near anything. For what it would cost a shop to do it for you I would do it yourself.

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DD: Cruze LT
04 Comp G: All dash no flash.
"I'm not an alcoholic but I keep a gallon of whine under the hood."
"My Grand Prix has a first name its W H I N E R."

You didn't lose the torque, it just moved up in the powerband a little as well as a bit more HP. Go with option 2, you'll grenade the motor on a 3.6 without at least headers. I still see a few degrees of knock with my mods on a 3.6

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Mods include-
Pulley boys 3.2 pulley, 20* timing, HPTuned, pacesetters, SSIC, modded 1.9's, F/R STBs on Don Rome brackets, 255lph pump, ZZP billet rails, GXP catback
Best of 13.4 at 103.... 12's this year