Farticcus of Plenticcus
Join Date: Sep 2003
72.5mm is about the biggest TB the plenum will support.
Even then, the 98-01 TB's can only handle being bored out that far.
71.5mm is the largest a 02+ TB can support.
80mm would not work,not only for the reason stated above, but IMO, you would lose too much vacuum out of the plenum, and that would cause other issues...like effectiveness of vacuum to the brake booster, and anything else that is run from vacuum.
So, no gain since no fit.