The pack, developed by Archibald Ingall Stretton, is a matte-black seven-inch-square cardboard envelope with tyre prints from the car embossed on the outside.
The pack carries the line, written in silver: "The race-bred BMW M3 CSL on a lap of the track at BMW's Performance Centre."
The words refer to the CD contained in the pack, which plays the sound of the car racing round the BMW track. As recipients open the pack, they read: "Now come and find out what it sounds like from behind the wheel."
The CD is accompanied by an invitation to an exclusive test-drive event, for a select number of sports car drivers.
Copy on the back of the envelope draws attention to the sound on the CD and encourages recipients to hear it for real. "Unless you're sitting in a glass-fibre-reinforced bucket seat experiencing 1.6 lateral G you haven't really heard the 360 bhp BMW CSL. But that can easily be arranged," it reads.
Alistair Bryan, an account director at Archibald Ingall Stretton, said: "The engine sound is as astonishing as the car. Using it to drive response delivered a unique kind of invitation that was supported by extremely high production values. This pack encapsulates the essence of the car without relying on performance facts and figures."
The pack was written by Jonathan Vinton and art directed by Martin Lythgoe.