How badly do you want one, I have a couple in boxes (many many boxes). One of the motors will need a full rebuild though, and it's not cheap.I remember when it came out. All of our RZ350s, which were the bike to have in the Light Weight Grand Prix class, became instantly outdated.
I wanted an FZR so badly in those days .. but I didnt have 2 nickels back then.
TBH, they're not really that much fun, get yourself an NC35 if you're looking for a 400. Having said that, I've one mate who loves them over all the other 400s. I have another mate who put one into the front of a car on the main street of town when we were 18 Cost him a cracked shoulder IIRC.