ok, this is the deal i broke like half the teeth off the ring gear of my 3:73 in my 97 SS, gettin on it. so i'm getting a new torsen and new gears. This is my question how will the 4:10 hold up with the 315 on the back, how will the shift points/ were at, etc. But this is the thing i think my 3:73 broke because they were whinning which probably means they where wearing on eachother and it ways just do time that they broke. So i'm picking up the slp used torsen from slp for $100 and i can either buy new 3:73 for 200 or get never used 4:10 from my friend for a 100.

 

I didn't see it in your post but if you have an auto trans, most say stick w/ 3.73. Especially for drag racing. 4.10s if manual trans.
315s will get some bite, but don't really factor into which gear to choose.
People use both setups with success. I run 4.10s with M6 and 315 street tires or ET drags. Gotta be careful on launch or my 10 bolt will be finished. That would be the case with 3.73s as well.