The last time the Dinan name graced the pages of Autoblog, Michael Harley was waxing poetic about the S3-R BMW 1M Coupe, a car that still stands in his ranks as one of the best cars he's ever driven.

Steve Dinan has been enhancing BMW models since 1979. But don't throw his company into the ring with the dozen or so other tuners who tweak, tinker and piggyback upgrades on the famed German marque.

Add the same kit to a 543-hp BMW M3 CS or any S58 inline-six, and the result is again 735 horses since the hardware is all the same. We sampled this extra thrust in Dinan's tuned-up BMW M4 ...