Check out this from Australian Top Gear where you get a sense of these big engined muscle cars.
Wiki says: 350 VXR8s per year were scheduled for official importation into the UK, at a price of £35,105. The LS3 V8 is particularly popular among tuners in the USA, so performance parts are widely available. The most dramatic warranted upgrade is the £7,000 supercharger kit, which ups power to 395 kW (537 PS; 530 hp). Imports to the US were previously sold as Pontiac G8, with V6, L76 V8, or an LS3 V8 engine in the GXP trim. The supercharged edition Bathurst VXR8 was reviewed on Top Gear, and its power-lap time was 1 min 26.3 seconds, a similar time to the current BMW M5.