I, too, am looking for a better rear shock. The only shock an independent dealer, (Jim's Cycle, Axtell, Texas), can find are #440's by Progressive, no other company list anything for the r3 that this shop has books on.
If you find another brand(s), I'd be glad to know also.
Yes, get Progressive 440's - if you are going to have more than 200 lbs of weight (rider+passenger+gear) on the bike. If your load is consistently less than 200 lbs, get Progressive 418's (all according to Progressive).