5'' 7" Intercooler FMIC for N54 N55 BMW 135i, 335i, 335xi, 335is5" INTERCOOLER FMIC An ARM FMIC upgrade is one of the best modifications for your 135i because not only does it yield an average of 25whp and 27wtq but it does so consistently. "How?" you may ask. When you increase power with a tune for example, you are increasing boost pressure and ultimately heat in the engine. When the ECU (DME) detects too much heat, it will actually reduce timing and limit the amount of power the engine can produce in order to