I chose a 135i because of the lack of "standard" options on the 128i. I was a little shocked at first that even a BMW nowadays DOESN'T have Xenons as standard. Mind you, I've never ever driven a BMW before, and I haven't even taken this 135i for a test drive. My car is coming this Sunday, Aug. 2nd and I'm very excited.
Back on topic, the 128 was also missing the big brakes, and a rear diffuser. After doing some simple math, it seemed like the 135i just had more even after throwing all the options on 128i. The 2 biturbos just seemed like an extra that was thrown on.