Great info!

Officially rated at a very conservative 250-bhp to keep the Corvette (255 horse) from having its feelings hurt, the Turbo T/A actually pulled 301-bhp on GM'* very own dyno and grunted out 340 lb-ft of torque to boot. Backed by a BOP 2004R automatic tranny, with a 3:27 limited slip rear, the hyperactive F-body ran a 13.5 quarter, hit sixty in the low-fives, and topped out at 150-mph.

What makes the 20th Anniversary Turbo TA so special is that it is a complete mechanical package, and not just some tape stripes. Starting with the engine, Pontiac borrowed Buick'* 3.8 liter (231cid) V6 turbo powerplant from the fabled 1986-87 Grand National. Some difference exist between the TTA motor and the GN version. Different heads were necessary in order to squeeze the motor between the strut towers. These heads, adapted from the transverse FWD version of the 3.8 liter motor, have the added benefit of improved exhaust flow and combustion chamber design. Subsequently, different pistons were required in order to maintain combustion chamber volume. Other changes to the TTA motor are a cross-drilled crank, larger 12 fin/inch GNX-style intercooler in place of the GN'* 10 fin/inch design, specially-designed stainless-steel headers, higher-pressure Bosch 237 fuel pressure regulator, and a recalibrated engine control module.

The Turbo TA came with the rare 1LE racing brake package, which upgrades the front discs to 12 inch police rotors, Corvette twin piston aluminum calipers and semi-metallic pads. These brakes are virtually fade proof, and were installed to legalize the 1LE package for Firehawk endurance racing. The rear discs were also increased to 12 inches in 1989 and use Corvette single piston calipers. All of the brakes on the car are of a quick change design, and pads can actually be changed in 30 seconds.

The only mid-year change made to the Turbo TA during the entire production run was a redesigned turbo inlet tube. The redesigned plastic tube was more durable, and had a clamping rib on either end to keep the hoses attached more securely. Other production changes in 1989 affected the Turbo TA and F-bodies in general. As an example, in March 1989 GM switched from glass to Lexan T-tops in order to save weight. However, the Lexan tops had severe problems with scratching and cracking, and GM had to replace most of them under warranty. During the 1990 production run GM switched back to glass T-tops after having so many problems with the Lexan ones.