Phil 
2005 BMW 5 Series Sedan 545i 4dr Sedan (4.4L 8cyl 6M)
From CL55 to BMW 545
 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.