find a head...
just find one for your engine.
let the boosted guys get the 99 head.
(speaking as a naturally aspirated dude who has a 99 engine that's ported a polished. phillyb hasn't driven his car yet)
"Rebuilt" bp4w on eBay is $480.00 project g sells for $450 but it serms to me that you are simply new to making bolt on power and I almost promise you have no clue how to go about making the 99-00 vics work with your wiring harness or what it entails to swap the heads. For the same bhp gains you will get from the head on a newbie car, you may as well invest in a great exhaust and intake, and/or save for someone to throw in some form of forced induction
A 99 head stock will flow as much as a ported 94-97 head, unless the you get some damn good port work done. The 99 head with equal porting will always flow much better. Head work on either head costs more than a 99 head. Have you ever priced head work? It ain't cheap.
It's your call. You are buying a 99 head used so the price matters on what you can find. No set price for obvious reasons.