Stock pulley and 4.10s are good. I would say it depends on what kind of tires you are going to use and how much traction you can get if you have a pullied car. 3.73 would not be much of a difference. 4.10 might be too much. Maybe not if you can get traction. 3.90 sounds like it would give a noticeable acceleration difference but maybe be a little more manageable than the 4.10 if you are pushing 450hp.. I really won't know about traction until spring but on that warm day we had a few days ago, I was able to get traction in 2nd and 3rd with my snow tires. On a cold day, 3rd will fry the tires when the boost kicks in. I need to get my F-1s back on or maybe a couple new GSD3s. How many days until Spring?
BTW, Hank. Speaking of wheels and tires, how's your search for a wheel key coming? Getting any comments about mismatched wheels?