Would these be a direct replacement on a GSR? I believe the 4-2 will be, but is the 2-1 longer than our stock ones, or will it fit right up to the cat? If not, what would I need to do to make it fit to a Comptech cat back?
Spoon improved their header design with the one-piece 4-2-1 header, the two piece looks kind of iffy to me. I doubt you'd gain anything from the two piece header, it's not very different from the stock manifold.
OK. But my worries about the one piece is that it would hit the ground if I was to drop the car if I hit a bad bump or something...I dont want to drop the car too much, maybe a 1 3/4" at the most (H&R Sport springs). Would that be a problem? Also, what would I need to make to one piece fit up to the Comptech cat back? And would the Comptech exhaust be too small for this header, and create a bottleneck? I would settle with an inch drop if that kept the header out of harms way...
Remember the header connects to the cat, not the exhaust. You will need a bigger cat with the proper flanges to fit a JDM-spec header such as this on your car.
I wouldn't get a big 2.5" header like this if you are sticking with the small 2.25" Comptech exhaust. It's really a waste of a $900 header and you'd get the same results with something cheaper. You should look at my old dyno with my old setup in the dyno section, I wasn't making much more power than stock because my stock-sized 2.25" Comptech was choking off any added flow the 2.5" 4-1 header was giving me.
Yeah, I know the header connects to the cat, so I would need a 2.5" cat, correct? Where do you get the proper flanges at? I will also need a 2.5" exhaust system also to prevent the bottleneck. Ok, but since its a JDM header, what cat backs are availible in 2.5" piping? Or will USDM cat backs fit fine? I just canceled my order on the Comptech Cat back..
SMSP on this board does that kind of exhaust stuff and can hook you up with a 2.5" Carsound with flanges already pre-welded. Check the common topics list in the Performance forum, there's a huge thread dedicated to 2.5" catbacks there.
Hey 2 more questions, Ive searched but couldnt find an answer. How much lower does the spoon header hang down than stock? And what would be the lowest I should drop the car to insure that the header will be ok?