DIY head porting with a dremel?

[treed2@u.washington.edu (T. Reed)]

Okay, well this is gonna sound stupid coming from an inexperienced
youngin' like me.. but..

With everybody running to pay a shop hundreds of dollars to get their head
ported, is there any reason I can't just do this myself?

I mean.. looking at before and after pictures of 16v intake and exhaust
ports on people's web pages, it looks like somebody just took a dremel
with a grinding bit and opened up the ports a little without making the
outside surface any bigger. I consider the dremel tool to be the
handyman's 3rd most important secret weapon (after vice grips and duct
tape) and I feel quite confident with a dremel in hand. I don't see any
reason why I couldn't just duplicate the re-shaping of the ports as shown
in the photos myself. Or is there something more to this that I'm missing?

Why do people send this work away to be done by professionals? Is it the
risk of taking off too much material and ruining an expensive 16v head?
Fear of screwing it up and actually reducing the engine's power? Or is it
just a sense of "if you're going to do something, do it right"?

Maybe I'm being stupid here and grinding material away like that only
helps if you put bigger valves in too..

Being a cheap bastard, and being that I'm going to be pulling my head
real soon now anyway to put in a 2 liter block.. I just have to ask
because if $20 worth of dremel bits will buy me some more ponies, I'm
game.

-Toby