No, if you don't if you plan to eventually overclock that cpu. Also, I don't see how a 2500k even at stock would bottle neck a 6950 when with built in turbo boost it can reach up to 3.8 Ghz, more then enough. Though, if you want to wait Bulldozer is suppose to be released June 7, and is suppose to beat a 4 Ghz i7 2600k at 3.5 Ghz at roughly the same price.
That CPU is so good at what it does it gives the Intel 980X a run for it's money (not figuratively speaking, it's hundreds of dollars less) in any program that can't use MORE than 4 threads. Basically, outside of the 2600K, you can't get a better processor. That processor can handle 2 6990's in crossfire, it definitely will be bottlenecked by that GPU, which for the most part isn't a problem, but games are become bigger and better on the PC. I read my original post, and a minor slip up in my text (yes, my fault) is what caused the confusion. I meant to say the GPU will bottleneck the processor.