Where are you at for 7k feet? And I can attest that a stock 5.0 at 7k feet is best case even with a stock 335, and maybe even a tick slower. With a JB4, I could see the 335 pulling on a FBO 5.0.
2010 E90 335i Black Sapphire
Best Stock 1/4 time = 14.1 @ 99.4 at Bandimere Speedway (DA = 7,400ft ASL; 13.5 @ 103 corrected)