Mate, I have K610i. And i flashed it to W660 3 days ago. The result is that I'm now searching for K610i firmware, as I will flash it back to original. It isn't worth it. Eventually, you'll find flash menus boring, but your phone will keep freezing. My phone sometimes doesn't even want to access applications and/or games folder. Then, when I manage to run walkman (by pressing play button e.g.), it freezes sometimes, sometimes does not.

My advice to you is to try. But I'm sure you won't find it worth of it ;)