Harmonics Streets? heh I looked up for my car with a 700 OD tranny and all and people told me if I plan to take it on a strip and street then don't go any higher than 4.11's. Go here, www.ckperformance.com and talk to a guy named Chris. Some people refered me to him and is supposedly a really great help and can tell you what gears to run, stall converter, etc. 3.73's sounds good to me though, that is what we had in the C20 at one time and they are great for highway use.