I have a greddy t78 kit. Bought it used, its a greddy mani, turbo, and dp but the dp dont fit. :icon_conf
Most downpipes are different due to turbo sizes and manifolds. either buy a 3" dp and have an exhaust shop mod it to fit, or have one fully custom made.
Just dont buy a 3" dp for stock twins, or else the pipe will end pretty much were your turbo mounts and half of it will need to be chopped off.