Of course, it still isn't street legal, so you'll need to haul it to a track to use it, but you can be confident of the GT4.R's performance when you get there.
It is a tribute to the incredible performance of the Camaro ZL1 that not only does the GT4.R include much of the street car's speed equipment for full-on racing duty, but the GT4.R's engine is actually restricted to a comparatively paltry 480 horsepower (down from 650 horses) because of the GT4 racing class rules that level performance among the various brands contesting the category.
The GT4 blends the factory ZL1 bodywork and hood air extractor vent with lightweight racing-grade carbon fiber doors and front fascia. The ZL1-lookalike front splitter and dive planes are actually custom GT4-compliant pieces, and there's a giant adjustable rear wing.
The mostly stock 6.2-liter LT1 small block V8 is supplemented with custom fuel inject and a dry sump oil system. But forget about the factory Tremec gearbox. That's replaced by a racing-grade Xtrac six-speed sequential transmission, supplemented with pneumatic paddle shifting.
Check this out: the ZL1's rear Brembo brakes make the grade for racing duty, but the fronts are predictably swapped for pure racing six-piston calipers.
Ohlins 2-way adjustable front struts and rear shocks provide the necessary suspension setup options. Front and rear swaybars are also adjustable.
Hopefully your budget is similarly accommodating.