2003.5 has LED tails onwards.
2003.5+ are considered to be more reliable with less issues.
If anything 2001 to late 2002 would have motor issues.
But overall excellent cars. Look for loose bearings on the waterpump, and typical signs of major problems, oil leaks, coolant leaks, valve cover or head gasket problems, abused transmissions or torn subframe, problematic covertible tops, worn rtabs or fcabs.
Otherwise stick with the m3's with led tails IMO.
What colours are you looking for?