I saw a video of someone putting one of these on a reference 670; I can't remember where, but yes, it fits.
Be well worth it!.
Let me explain in a very simple story why this cooler rocks.
GTX470 - 80% fan speed, very loud, but could blend in during gaming and I could ignore it. Temps, would get up to 90c in Battlefield 3, or other intensive games that use 99% of my GPU.
GTX670 - Never tried it with stock, but most reviews put it @ around 85c, 99% usage or so. Loud when maxed, supposedly, as well, louder than my GTX470 according to Adanteche or whatever.
GTX670 /w this cooler - idles @ 24-27c. Cant hear it at all, no matter even if I max it out. During gaming? Battlefield 3...51-53c. That's @ 99% usage, in games like ArmAII OA - I get 55c.
I'm not even breaking the 60c barrier here, overclocked, and @ max usage for prolonged periods.
Can't imagine why I'd spend double for the tri-fan version. These cards are rated to to to 90c, as most are, staying @ under 60c, while over-clocked, and inaudible...is awesome.