Reset is only a temp fix to alloy you extra time for proper fix but should never rely on it as a permanent due to the brushes ware and the pressure cylinder or whatever its called possibly be at the end of their use
Have you checked the front and rear sams for any moisture damage on the soldering plates,ecu plug connection?These are not that bad to find issues.Was the terminals crossed by any chance or jump started?I can pop round sunday with an ecu kit to rule out the problem if u want as I have 3 w211 I6 lol
Having seen it in the flesh I can only say didn`t expect any less than a stunning and shiny beast.U`ve given me an inspiration mate,now my estate is on the road so hopefully down load the file for modifying and map it tomorrow.
I sold my S class to my customer with a p/x his 2006 320d and a few day later I asked him how is the car?The answer was "IT AMAZING " lol they are indeed.Get it mapped and give it more spirit when needed u`ll love it even more.
Hissing and whistling are not the same sounds.Usual turbo pipe split is the pipe on the right as u face the engine thats hissing noise.Take the belt off and check the pulley,should lock up clockwise and turn anticlockwise if not turning anticlockwise pulley is seized thats yr whistling noise.