Can you explain your thoughts on the switch?
Just wanted something different, or you feel the 640 is doing certain things much better than your F30?
'98 Dinan/RMS stage 2+(VAC cams, CES Cutring etc)
'15 Buick Regal "T"(wife)
'06 Saab 9-5 Combi 5mt (full suspension, LSD, clipped turbo etc)