Originally Posted by scoobystas
Not sure the gear box is the issue, the shape of the downpipe between jdm and usdm is identical as far as bends and the way it sits, so in theory it should fit with both gear boxes.
do you have a link to the downpipe in question? Are you sure the turbo is seated properly with the uppipe or uppipe with header, as an improper angle in those locations can cause your issues.
I thought they would be exactly the same too. Laying my UDSM Perrin DP next to the HKS one, it is pretty clear that the HKS one has a stronger bend to it. I will try to take a picture tonight when I get back from work. But basically from some research, I found that the STI crossmember sits about 7/8" higher than the 5-speed, which would make sense why this DP isn't fitting as it needs just about a 1/2" of clearance to fit.
The turbo, exhaust manifold, and uppipe are all seated properly, as I was able to install all of that on the engine stand before dropping it in the car, and the turbo is properly bolted down.
Either way, looking to have this issue solved soon, whether it involves cutting up the DP to make it fit, or just a good ole heat-n-beat method.