Macka,
It's still running standard boost, so I'm guessing (and only guessing) that a mid 13 might be possible as is, hopefully
with the power fc, cam gears and 1 bar 12's should be gotten (as long as I can learn to drive it properly)....
I thought GTR's do high 12's standard ? This is what i'm told by people i know who pull themselves over these (sorry for offending) king of the road GTR's ?