z00lander

I currently have a 2000 s4, mainly stock. I have the cats and resonator removed and have an apr stage 2 flash. But I just hit 83k which means everything is breaking now haha. Since I'm replacing the timing belt/water pump, etc I'm going to build the heads since I'm gonna already be in there.
I've been looking at 034motorspors.com at their oversized valve set, valve spring set, hydraulic lifter replacements, and possibly a head spacer to lower compression for now.
I'm basically starting a huge project before I was financially ready, so I'm doing everything in intervals. I'm building the heads first, then garret gt30s or a single conversion, and then building the bottom end. I would like to hit 600whp on pump gas when all said in done. But every modification, has to be able to withstand the ultimate goal as I want to touch everything just once.
Does anybody have any experience with building the heads. My friend is the best mechanic I know, and has plenty of cars in magazines. He is going to port and polish them and upgrade its internals. I have been unable to locate any cams and don't know if thats because they dont need to be upgraded or what.
I'm hoping somebody has done something similar and can recommend the proper parts for me to purchase. And if you've done something similar let me know the gains you netted. Thanks!

quickaudi:STFA

if your target is 600, you better build the internals as well, not just the heads.