I just bought a Quick 36 with the 13 hp Briggs Intek engine. The price and compactness sold me on it. I love the mower, and the engine is ok, but not nearly as smooth or quiet as my Kawasakis or Kohlers. However, I have a 14 hp Kawa that has barely been used and runs perfect. I'm almost certain that the mounting bolt pattern is the same (need to take a couple more measurements). I think you all get where I'm going with this.... Yes, this would probably void the warranty, but I think it would be worth it. The commercial warranty is only a year anyway. The muffler on the Kawa is mounted to the side, and would get in the way of the gas tank, but I could easily have a pipe welded to bring the muffler out front. I've swapped engines before, so it wouldn't be a problem for me if it can be mounted. So...what do you think?