We have tested it on dyno. It is not such a big deal like some people say. My stock has 203HP, with 325 inlet manifold, 224HP, but with noticeable Tq loss in midrange(it is too lean) and lowrange. MPG was slightly worse. Still not comparable to M3. I reverted it to stock, modification must be more complex than this(exhaust system, injectors, fuel map,...)
Don't know. I am satisfied with stock engine, I drive slowly. You can't drive fast in convertible, it is twisting a bit in corners. Not much, but I bought convertible for another benefits than racing. But maybe one day I will try what potential is in 2.8i engine.
No chance guys. But I have different BMW(e30 325i) for experiments. Planning to swap for V8, BMW M62B44, street legal, lightest as possible. 210kW, 325 lb·ft. But I have to finish current projects. My income is considerably lower than before, so it takes much more time to finish things up
P.S.: I found Fiat 500 from 1969 in uncle's barn under hay. 99% in original condition, 17bhp I love this car.