Steve Dinan has been enhancing BMW models since 1979 ... an engineering firm that writes its own software, builds its own parts and then backs everything it does with a factory-grade warranty.

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.

Dinan sold his company in 2013, and our recollections of screaming inline-sixes and V-8s started to fade. Enter CarBahn, ...