AIr density make a big difference. Phoenix 2500ft z'z are solid 14sec cars.
thanks hatch20 for backing up my FACTS
ninenty % of the z's i see on the track where we go in kentucky run low 13's to mid 13's. but i dont know what there mods are. i did see a twin run low 11's the other week though.
lol then if where u live z's run mid 13's my M3 must run high 10's