Having come out of a CL 55 Merc. I found the BM only slightly slower. The BM's road holding is better, however its economy is the same as the 500bhp merc. The BM is a boring drive but I can live with that. I miss my TV and seat heating.
Seat heaters, throw away the I drive give us more buttons to brighten up the Cabin. Improve the exhaust note to at least a growl. You want to hear a 4.5 V8 growl.