I have $875 to spend, and Ive decided to put it toward a set of 200cc ProAction aluminum heads. This price is for the unassembled heads, so I will need to buy the parts to assemble them. I was planning on Manley Race-Flo waisted-stem valves, but I havent heard much feedback about them and Im not one to buy into something without researching it. What are you guys using and what do you think of your choices?