FWIW, I have VRS for FS9 and get anywhere from 40-70 FPS, granted I have a high end system but it runs fine. I too, am a little concerned with FSX. I stopped using FSX when DCS Blackshark and VRS Superbug came out. Only started it again lately when the new HUD by Neutrino and the new carriers by Fernandez came out. Now I split my time between FS9 Superbug and Acceleration F/A-18. What brings me back to FSX are the carriers. Just my two cents.
Paco
3.3 ghz i7, GTX295, 6 gig RAM, Track IR5 (busted at moment), X52 Pro