Hi I was wondering, I keep seeing all these stories that the E39 M5 and other BMW engines around this age are not putting out what they should be. Most cases seem to be around 340bhp for the M5! Is this true or are they horror stories? Coming from a vauxhall combo 1.3 it feels fappin quick to me! If true is it worth a remap? Also on the tuning side if all is well and no remap is needed is it worth chipping for any noticable gains in fuel economy whilst cruising around?
Any help is greatly appreciated.