An ARM F30 Intercooler upgrade is one of the best modifications you can make to your 335i.  One of the F30 335i's most significant weak-points is its stock intercooler.  This becomes obvious when tuning the N55 to increase boost with a Stage 1 tune and even more so with a Stage 2+ tune.  With a higher boost target the charged air coming out of the compressor is hotter, therefore increasing IAT's.  To compensate for the higher IAT's the ECU (DME) reduces boost, timing, and overall power to the engine.  This is the exact opposite of what you want for getting your F30 335i to run faster.  In order to keep those IAT's low, a larger and more effective intercooler is needed. 

IN THE BOX