My position on the 1M would be dramatically different, however, had it been fitted from the factory with the truly fantastic 4.0-liter V8 from the E92 M3 (the last great M car, in this writer's humble opinion).
Matt Farah of Drive took to the wheel of a 135i that's been completely reworked by Performance Technic and is owned by Marco Svizzero. The car required a salvageable E92 and what we imagine is an incalculable amount of wrench time, with the result being, as Farah says, "possibly the best BMW you could build at any price." Oh, and it sounds absolutely delicious.
Check out the car in action.