Chuck
If you take the train through to Monaco you can walk round the Grand Prix track, take in the many Ferraris, Lambos, Bentleys etc which are everywhere, and you could also visit Prince Rainier's motor museum filled with many of his own cars. When myself and my family were there last summer there were lots of interesting exhibits including a number of 50s & 60s American cars which Rainier has a particular fondness for, possibly influenced by Princess Grace when she was alive.
If you're a Ferrari fan, and lets face it, who isn't deep down, Monaco is full of memorabilia stores just about on every street corner.
The train ride only takes about a half hour from Nice to Monaco and they run frequently.