Check out the m5board message board E39 section , and do a search there. These topics (540i vs M5 and 2000 vs 2001) have been thoroughly discussed there. In short...get the 2001 M5.
2011 M3 Silverstone/Silverstone 6MT
2001 M5 Lemans Blue/Silverstone
2007 328i wagon
2006 330i ZSP 6MT