I have a 2006 250 XS serial 1E001029 that my mec. thinks its about gone. we talked about a new mercury power head only no external parts. then i would pay his labor to put my old parts on it , compressor, fuel rails , coils , ect. For $3500.00 or so more i found a fully dressed mercury . will a fully dressed motor have everything, including compressor, ecu, coils , ready to go . and will this come with a 2017 serial #. my 2cd question is will a 300 XS powerhead bolt on what i have .