Pillow mounts definately make your car a little bit more uncomfortable to ride in. Not only that, but they "knock" when you hit a bump. Personally, I cant make my stiff enough so I would re-invest in them if I ever got a chance again.

Ive heard the knock when Ive owned my GAB Revostrokes (sold), my friends ITR, and my friends MR2.

So, its not a fluke after all, hearing the "knock."