Yes, I can tell you from experience... porting your pistons will just let them fail earlier. I had a piston break the skirt off and bugger up a top end. Jacked a set of VForce 3 reeds as well thanks to all the crap banging around inside the cylinder. Had to buy a new top end, gaskets, o-rings for the head, and new reeds for that one side, thanks to a broken skirt. lol
Don't port them. For the 1 or 2 hp you MIGHT gain, its not worth the added risk of a broken skirt down the road.
- Jared