I chose the 128i for several reasons. Turbos create heat, heat kills engines. The extra HP is NOT worth it. I mean really, most of the time you have to stay within the speed limits. Through my 35+ years of experence in sports car ownership and racing. I know the damage turbos can cause if they are not spun at high RPM's My 930 Porsche turbu burnt valves and cracked head studs. $16,000.00 for repairs on a car that had only 15,000.00 miles.
The 128i has pleanty of get up and go fro my needs. If I want to go fast I get into my Porsche 911 NON turbo car and fly!
I think it is all a matter of taste, my 128i is my daily driver. I run it hard and am pleased with the performance and speed. If I lived in Germany and had the autoban I would consider a 135.