Though... (I know, double post, stfu already) best 1/4 mile improvement was definitely my suspension... find an adjustable shock/strut with some Eibach pro-kits (total price tag for the D-specs and Pro Kit for me = $729.00) and your 60 foots and overall times will drop like mad... my best 60' went from a 2.20 to a 1.97 and my best 1/4 time went from a 14.173 to a 13.805... consitently running 14.22s to now 13.90s in a convertible.