Going to 3,90's from 3.55's would be a waste of money, if you want to drag race seriously 4,10's are entry level, 3.55's ere designed for road racing, and for N/A cars they are usually the worst gear for draggin' causing you to shift 4th too close to the finish line.
I'm sure I'll get slammed knocking 3.55's for drag racing, but 15 years of experience has proven 3.55's are not for drag racing.