If you go from manual to a stock 5R55S auto it's quite a job, believe me. If you go to a C4 or a 4R70W it's pretty much a cake walk. You see, the 4R70W and C4 trannies are ''dumb'' like your manual, so it's pretty much just switching the drivetrain components and making minor wiring mods. The 5R55S is smart and requires a lot of wiring harness section changes amoung other BS. I'd suggest a 4R70W and even a GM turbo 400. The 4R70W will give you great gears. The pedal assy on the floor takes about 20 minutes to change so don't sweat that. Just go on the other forums and do some questioning and searching. You'll see, it's nothing. If you want I can hook you up with a guy that's done it and knows all the details.