I just did my RX-8 This weekend with Honda Pro-Shine. It works great, but I think that some of the newer spray cleaner/polishes specifically for cars may be the way to go. Don't get me wrong, the RX looks great and there wasn't any concern about overspray or residue, it's just that I went through a whole bunch of it.
I use the "California Car Dusters" to wipe off surface dirt and grit, works like a charm for quick "dustings"
Hell the California car Duster has also found it's way into the house, NOTHING dusts better than these things. It traps the dust as well, doesn't just push it around.
So I'd say hit it with a Car Duster, then the Pro-shine or similar product. Should work great.
For the record I didn't wash the RX-8 first. I just dusted it, then spay and and wipe with micofiber towels. No Foolin. Been cleaning my Black Busa for 3 years now using the exact same equipement and she shines like new.