Low mount turbos are nothing but trouble.
Put that sumbitch in the engine bay where it belongs.

I went with the turbo size that Trick Performance uses on their
base kits. A Turbonetics 62-1 with .81 a/r. It is maxed out at about
12psi but should be just right for you like it was for me.

I've got a front mount 4.8 build about to wrap up here right after
Christmas