http://www.deltafaucet.com/search/re...#axzz1dujnyrlK shows the choices of just the rough-in valve. I'd probably go with the R10000-UNWS, but it would depend on what your piping is, as to what's the best. The letters decode as UN- universal connection - either screw on or solder in; WS - with stops.
As said earlier in the thread, with this rough-in valve, you have a huge choice of trims and control means (including single handle, or two handles with either just temp and volume, or thermostat and volume). If you go to http://www.deltafaucet.com/bath/tubs...tml#1873294718_ and select the R-10000 rough-in, and then specify what you want, it will show you your options. While Kohler makes some nice stuff, it is a major pain sometimes getting parts down the road. Delta's stuff tends to be backwards compatible...Kohler's seems to be the design of the day with little regard to backwards compatibility.