E63 BMW 6er as a everyday car

Hello together, at the moment I drive 3 cars, as a daily car an e46 330i as a seasonal car no.1 a 350z as a seasonal vehicle no.2 an e63 M6 I am satisfied with all 3en, but for running costs I would like to reduce the fleet to 1 Alltaugsauto + the M6. Both the e46 330i (M-Package 2 + SMG) as well as the 350z(20inch, Bielstein suspension, Nvidia system + Sport Kats, Chip etc…) are great. The 3er is allerweltsfahrzeug, the 350z in the SOmmer in the dry The M6 is kept….only for what can I exchange 330i and 350z, which is just as suitable for everyday use and makes as much fun as the 330 and 350z? Thought there was an e63 645ci or 650ci….. The M6 is a KOstengrab, which I drive only about 4-5tkm in the summer, as everyday car is not so good. What do you think?