I would recommend the faster, and less power hungry, GTS 250. Also, the extra memory is a nice bonus. Should oc very nicely as well with that nice cooler.
And ya, you do have a lot of posts 😀 Still, getting the newest thing with these cards isnt always best, there is personal preference and situation. For instance, keep in mind, 9800 GTX's will SLI with the GTX+, but not the GTS 250. A GTX+ is both forward and backwards compatible.
So, I already had a 9800 GTX, if I wanted another for SLI i would look for a GTX+. But I diverge, you are talking about folding, not SLI.
My recomendation still stands, I dont know a whole lot about sparkle. Anyone have any experience with them?