I've heard that you don't even need to mod the suspension, because the all-aluminum corvette engine isn't really heavier than the stock engine.
In other news, there is a company shoving an all-aluminum, dual-turbocharged V8 putting out like 1200HP into a Lotus chassis, which out-accelerates the Bugatti Veyeron to 200MPH--with rear-wheel drive, no traction control, and a regular 6-speed. I thought a chevy V8 was an odd choice but apparently the modern aluminum ones are pretty amazing in terms of power-to-weight. Apparently, there really is no replacement for displacement.