I was going to $25,000.00 more for a new M3 Coupe but decided on the 135i instead. It was a wise choice for several reasons. This car is as fast as my 2007 M Coupe that I turned in after a two year lease. In fact, it's faster in 2nd gear then the M. The twin turbos are smooth and there is NO turbo lag. The 135i is not only fast but it has a very smooth and quite ride. The car handles extremely well and there is a great engine sound when you get on the go pedal. The 135i is really an M car for all intents and purposes! There are so many after-market options available through BMW Performance, that you can really have the power and performance of an M.
The BMW 135i has every option that you could ever want! One of my favorites is the Comfort Access... all you have to do is touch the door handle, get in, push the start button, put it in gear and go. The Premium Sound System is awesome and the interior fit and finish is top quality.
My main complaint is with the Satellite radio! It hasn't worked properly since I leased the car. At this time there is no fix but BMW is working on it. A better paint process would reduce minor flaws.