Hi, always great to see a new project getting started. My two cents, the T5 is by far the most popular as it's really fun to spool up and then blow off boost with every shift. Nothing transmits the thrill of boost like a manual transmission. The T5 will last forever and you get overdrive. The C4 is best if you need to handle a pumped up turbo in a drag racing setting. Having run them both, and like them both, I currently run the third (least popular) option, the A4LD on a stand alone platform. For my medium HP (225 - 250) Pinto, it comes off the line very hard with a 2800 stall, holds boost through gear changes, has overdrive and a lock up torque converter. Have fun building !