I have a '94; last year of the 4 speed, and I just got the parts to fix the starter gear issue for $100. See this link.... (if you haven't already...)
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1288911670/0Even this I don't think would prevent me from buying a 4 speed; most of those bikes ran fine for ages without the gear issue; but it's such a quick and easy fix, and inexpensive, that I decided I might as well while the bike is down.
A lot of guys here LIKE the 4 speed BETTER than the 5 speeds. It's a matter of taste, but with a motor that has a whole whomp of torque rather than a bunch of top speed, it makes sense. There's plenty of power for the gears, and you're shifting less while riding more.
Besides; $650 is a pretty great price, especially now in the Spring. I got my bike last Fall for $250 (it was a special deal friend-of-a-friend thing...) but saw several listed around $500-$800 that people were just getting rid of. Lately, I haven't seen any under $1000.
Check out my build thread in the signature line below... RYCA-esque, but not RYCA...