I've had both and I run about 185. The Bontragers will flex like a rubber band under your weight. The K's aren't a lot better in that department. I think riders in our weight range need to think about more spokes than those two wheelsets offer.
I bought a 5.9 SL last summer, too. That's where I got the Race X-Lites. I had been riding Ksyrium SSC (the version before the SL's came out). I tried the Race X-Lites for a while. They're terrific wheels, light and roll well. But they flexed so much I could hear 'em rubbing the brake pads on steep, out of the saddle efforts. I put them on e-bay used and got $600 for them. I agree with the previous poster that you shouldn't even ride them. Put them up for auction as new and unused and you will get more than enough back to go out and get a top-notch set of hand-builts designed for your weight.
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