PM Yamablue RX1 (Chris), as he can help you with the OEM setup, and may save you some dough. He literally has a notebook on the various calibration changes he's made at varying rider weights too. Using his suggested starting point, I was able to get the OEM shock to work pretty good, much plusher than my Ohlins was. It is important that the skid is setup properly (control rod, control rod gaps, spring pre-load, straps, FRA, etc...) or it will ride awfull. If nobody works with you, you'll have a tough time of it.
I bought the Ohlins rear clicker in my '04 RX-1 before Chris got a hold of me. Unfortunately, with the W-arm issues I've been having, I'm seriously looking at the Expert-X.
If you still decide to go with an aftermarket shock, beware that Ohlins shocks come with a very stiff factory spring when ordered through your Yamaha dealer, or Ohlins distributor and are a very aggressive shock calibration. I had Bruce from Pioneer install a softer spring and that helped ALLOT!, but I can only tolerate 1 click from full soft. A revalve should help that? Check out Pioneer and see what they have to offer, as they set the shocks up according to your profile. I would also look at an Alum. bodied Kayaba offering from either Pioneer or Maxximum as it is substantially cheaper than an Ohlins or Works, or Elka, and is rebuildable. If you can find some, the Viper replacement/upgrade shocks work wonders for the Pro-Action too.
In hind site, If my OEM didn't fade I would've kept it. But because it did, I would've gone with an Alum. Kayaba from Pioneer instead of the Ohlins.