Well with the kind of money you seem to have. I think you could lease another M3 without getting rid of any thing. Also, I know I can only speak for myself. But for me it would be very hard to trade F430 for any M3. I love M3's but a F430 is much more special. It should only be traded in for some thing equally special like the Ferrari 458 or Maclaren MP4C.
nick named "BAD 3"
Cobb tune, RennArt catback non resonated exhaust, M-sport steering (racing alcantara & retrofit M3 paddle shifters.), Alpina B3 transmission flash, AFE powered sealed CAI, LED angels, E93 M3 Front Swaybar, 235/35/19x9 front & 275/30/19x9.5 rear. When in doubt...flat out