Don't go out any buy something that's factory OC'ed if its more (The only difference between the GTX 460's are bus sizes/memory, clock speed and cooler). You can do it at home without voiding any warranties (And get the same result). I have their Cyclone GTX 460 and can get it to about 890/2000 w/o voltage adjustments. If I like it unstable I can get about 918/2100 w/o voltage adjustments
The GTX 460 has a lot of potential for OC'ing, and they seem to run pretty cool. 1 hour of Furmark at 890 was 70 C's, and stock wont push past 60-63 (All with auto fan).