Im not sure as to what size ehaust i should run for my turbo setup. I have a fullrace topmount, and a 4" DP. i will be boosting 28psi max, and i dont know what exhaust to get, if any. would open DP be ok? i know it will be loud as balls, so im kinda iffy about it, and i dont know if turbo cars need back pressure like all motor cars do..this is my first turbo build, and im attempting to go pretty big on this build. i will be driving this car on the occasional sunny saturday as well, on probably 14psi. help.