go at least 3:55, too many guys on this site are simply too conservative, nitrous or SC, 500Hp or 900Hp, its all good with 3:55. for those VCA and authoritues that say you cant hook up with anything over 3:55, I say you cant drive! I drove a dealership owners viper with 4:10's and it was easy to drive no problem felt great. only drawback was i wouldnt take it on highway for long trips. if i would have known then what i know now i wouldve got 3:73 not 3:55 (4:10 not for me as i drive wayyy too much for them gears). now on a lighter note if youre not a daily driver like me and racing and high HP (600 or more) stick with 3:07 or 3:55, again depending how good you can drive.