I have a 2008 335 with FBI and upgraded turbos and probably pushing about 600rwhp(or looking to get at that point).my auto trans has 50,000miles at this point.i have done the fluids only change few times with redline D4 and dont beat on the car.car has had the alpina flash for years. Was thinking about going the xhp route.is there a big change from a Alpina to xhp? Probably I would do the stage 3.also is it safe to just do a switch and nothing else to be done to trans?
