Why doesnt anyone try to....

[naptown]

Port and Polish their own heads and intakes and such?

[Magnus]

several of us have done our own intakes.

Heads it takes skill. You could do a crappy job and be worse than stock.

[Drone51]

slacker did but had the wrong springs and his valve guild seats needed to be milled, if all goes well I might have some of my own soon too

[oil pan 4]

I do all my own P&P and light machine work.
Heads, intake, wireing harnes from time to time, machine valve guides, cut valve spring seats, cut valves, lap valves, block off internal EGR ports in side the heads.I allways buy my own cams, valves, sprngs, locks, retainers (usaly from ebay) I never buy kits and learned how to figure injector sizes.
I don't like paying some one to do stuff I can do easly my self (and have fun doing it).