Quite a few comments about 135's breaking down. You guys whine about 135 owners making fun of 128's all the time yet do the same exact thing. Thats OK though. We understand your motivation.
BMW is a smart company and covers all the niches in the car buying world. There is a big market for young guys with not alot of money who fantasize about being helmeted racers, those who dont care for high performance cars, dads buying their daughters their graduation cars, those who buy commuter cars, the older who still want somethin a little 'sporty' and BMW themselves for their own loaner fleet. The car serves this purpose just fine.
By the way, there arent alot of performance parts available for the 128 because......its really not a performance car! BMW themselves designed it as such by simply using a soft magnesium/aluminum block.
The 135 has beefed up, forged internals to handle much more power than stock. BMW designed it that way. With nothing more than an inexpensive 20 min flash you can turn up the wick on the turbo cars over 100hp.
128 drivers work like hell to squeeze 10hp into their engines. Love the way they also add up the total hp gains by using manufacturers 'claims'.
Rarely see a before/ after dyno to show actual gains.
The 135 might have an additional item or two that the 128 doesnt have but that goes with the territory. You pay to play. Yes, I would rather have a 12 cyl Ferrari as opposed to an 8 cyl one even though there are more parts that might possibly fail. To use this excuse to try a belittle a car is flat out reaching for straws.
There are many 135's making well over 400rwhp 450 ft lbs! Many of these cars do it relativley trouble free. Its rare to even find a dyno of a 128. Wonder why?
The 128 is a nice car but its just not a barn burner and cant be turned into one.