I have a 2008 g35x and have been looking at mods that will actually make a difference, I've seen a lot of posts about how much power high flow cats/test pipes, y-pipes and intakes will/will not make and have so far decided on the following:

Stillen Gen 2 Long Tube Cold Air Intake - $~550 Gen 2 over Gen 3 because I'm in a very wet/rainy region and I don't want to hydro lock
ISR Performance Y-Pipe - $~270
Kinetix High Flow Cats - $~410

I'm not looking for huge power but better handling because the understeer/roll on an X is pretty bad, I'm hoping for maybe ~20-30 whp with an uprev tune and the listed parts
I'm going to also be getting a grounding kit and have been looking at a Hotchkis REAR Sway Bar because the rear sway bar on x models are also very thin compared to the front and other models. I've also seen people suggest a 370z rear sway bar because it will be a cheaper alternative to the Hotchkis sway bar and is only slightly smaller but can't seem to find very many.

An upgraded throttle body doesn't seem to have much if any improvement at all, I've also seen posts about a TransGo Shift kit but can't find very much info on it.

I'm expecting my current list to be around $2k, any suggestions are greatly appreciated, as well as how to push the HR further in terms of power.

 

Definitely prioritize the swaybar.

TransGo kit is the bomb. It makes a world of difference, and will extend the life of the transmission because the OEM soft shifts cause wear. On my 2006 coupe, it'll chirp the tires under full throttle from first to second, and the shifts are solid and much much quicker. Downshifts for passing give a pretty good lurch too! But under normal putt-putting around town, you don't even notice it. Best of both worlds!

 

I just did the Hotchkis front sway and Cusco strut tower bar. Turn-in/body roll is greatly improved. The rear sway will be installed with the new exhaust and I expect great results from that suspension mod. Yes, the x has too much body roll in stock form. Beefier sways help a lot.

I think 20-25 whp is a good expectation with what you have listed.

 

Yeah, I have the 5AT(obviously, I don’t think they made manuals for ‘08) and shift speeds in sequential can be pretty slow, especially when dropping it into 3rd to pass someone. I’m wondering how big of a difference the grounding kit and then the transgo shift kit would make. It seems like the grounding kit only makes a difference on certain models and most posts I’ve seen are mainly about 06’ and before but both said it can drastically improve quality of electronics inside the vehicle and give better throttle response/shift speeds. It also seems like they’re affected a lot by rust? Which could be big for me because I’m in the Pacific Northwest and it’s always raining. $100 is pretty steep for some wires though and unless there’s a cheaper kit it might be worth it to just learn how to make them myself.

First 2 mods are definitely gonna be that and the sway bar though.

 

I have an 07 G35X Sedan, whats the part number for the TransGo kit?

 

https://www.z1motorsports.com/transm...at-p-9755.html

 

I added the TransGo kit to my March 2022 project list along with a pair of Corbeau A4 seats, provided the correct brackets can be sourced.