They made turbo Grand Prix's in the early part of the 90's. Front driver though. Can't think of any rare performance Pontiac G bodies. The 2+2 Aero Coupe is the only rare oddity I know of, but not really a hot rod.
I test drove one back in the early 90's. Fairly quick for that time with a 0-60 time of about 7.1 seconds if I recall correctly.
Here are some specs I just found (they were made in 1989-1990):
Stock Specs
Model: McLaren Turbo (limited edition) Grand Prix
Engine: 3.1L Intercooled Turbocharged V6
Horsepower: 205 bhp @ 5200rpm
Torque: 225 ft-lbs @ 2100rpm
0-60: 7.0 sec (source: Road & Track)
1/4-mile: 15.3 sec @ 89.5mph (source: Road & Track)
Transaxle: 4T60 4-speed automatic w/shift points and oil pressure unique to the TGP
Suspension: Y99 Sport Suspension (factory), TGP-specific springs
Wheels: Factory 16"x8" metallic gold aluminum crosslace manufactured by Alcoa, 5x115 bolt pattern, +25mm offset
Tires: 245/50R16
Exterior Features: Factory stock, McLaren Turbo special ground-effects, factory gold plated "TURBO Grand Prix" emblems
Rob