What's the reliability of the Audi 4.2 V8 like?
It could be a good option. It's already being used in the Gumpert Apollo and the Spyker C8. It should be a widely available option given its many different applications and trim levels:
Audi: S4 (B6 & B7), RS4 (B7), S5, RS5, A6 (C6), S6 (C4 &...