stock twins setup making 550hp max on race gas? no thanks. id rather go single billet dbb 6265 on a log mani, make more power on lower octane gas with nearly the same spool characteristics.... only beneficial to upgrade the twins if you are a diehard stocker fan and love the sequential system, or you live in cali and are afraid of tickets.I didnt know they did it... do it yourself. Its not that hard at all.
And dont rebuild.... upgrade