The engine has regained most of its original smoothness. I felt that the engine got a lot 'rougher' after adding the CAI, it would pull differently at different RPMs, in the manner of there seemed to be some flat spots on the way up to redline (around 3000-3500). Now, however, the engine is much smoother and pulls in one powerful motion, and seems that there is no drop off in power at any RPMs. Pretty stoked...