I did some dyno testing witht he garrett turbos
things that worked......
Larger Air to Air IC, but only when the runs were short. Otherwise the pressure drop was nothing but lag.
Jet Hot Exhaust and Turbo
Extrude honed turbo and exhaust manifolds, mine was not a rear mount, so that may not matter for you.
Ported and polished heads. Extruded haeds also worked but the process can mess up the valve seating area.
Sprayer for the IC ....not in the engine bay for our cars, but you could get creative.
NOS 50 shot. Does wonders for it.
The only place I think you have to run an addl cooler is the rear window area. Do a top mount with reverse louvers to feed it, at the expense of drag, or feed it through the upper intake vents, which sounds like your plan.
My experience with turbos or blowers is they all heat soak at some point. But you should surely be able to spank all but the 1% of Supra's or Viper's with the Whipple set-up alone. The TT package is off the charts in power, which presents all kinds of other fun things to work out. I think I would speak with Torrie/Hennsessy as they have a ton of experience in this arena and likely know just what to do for the GT. Mihovetz is also a good source, but he run's 1/4 mile at a time, world record holder 4.6 TT.
Are you really getting beat on power?, traction, gearing and tune have as much to do with it as the set-up itself IMO.
Just curious...where do you get spanked.....Drag race from a dead stop.....roll on from X mph in X gear, road course?
I say this as my buddy can smoke me in his blown C5 at certin mph roll on's to X #, in X gear. But when in other gears I whop his behind pretty badly. The same goes for his C6 Z, but after X mph it's game over for him. His gearing in both cars is better for this purpose and both cars are lighter to boot. Mine is bone stock right now. When I pull him later in the run he thinks I am sand bagging.