I wrote in my comparison the side mounts IC won't work on autos, but if you have a used T25 I would recommend getting an external wastegate. You would hate to accidentally run 8+ pounds of boost because of a busted internal one. The spring that your friend was talking about is the one that are on external wastegates. They have a spring that is adjustable and on it's lowest setting they run about 5 psi. After about 12psi the T25 start to run hot. They are good turbos and I've seen 13.5s GST's. From www.roadraceengineering.com you can get a vey good Griffin FMIC for $500 and run a reliable 8psi all day long. Just about any muffler shop can construct custom IC tubing using prefabricated mandrel bent elbows and stainless steel.

Skrilla
'97 Base Talon NA
"Technology is the Only Substitute for Displacment"
"Peace and Turbo Grease"