I agree with all of the above. My issue comes in when people think they are saving money somehow by DIY. It simply isn't going to happen. Once you properly educate yourself and properly equip yourself ( no..not a dremel) you are waaaay past what a professionally ported cylinder from a reputable builder costs. Then you have sub-par results...unless you have several sets of cyls and a dyno to evaluate the results.
Btw: unless a builder has a dyno, or one at his disposal anytime he wants, IMHO, I hesitate to call him " reputable". Also.. If the builder doesn't at least test ride/race his own work from time to time, I hesitate to call him reputable....for the simple fact all he has to go by at that point is 2nd hand info ( customer feedback) which may or may not be accurate.
Sent from a van down by the river