I've been doing some research on the site about changing rear gears... looks like I'm going to go with 3:27's. Will a differential (case & all) from an Auto SC fit into my '94 5-speed SC? Are they all the same except for the gear ratio? Also, it says I would need a 19.5T Speedo gear... uh should I go with a 19T or a 20T? I'm running the tire size of 255/50/17 (Tire manufacturer says 27.1 for tire height). If this all works, I'll be looking for someone with a rear end from an auto sc.