98 camaro

I have a real simple question....i'm looking to get some heads for the Z. What do you guys do that buy used heads on here? Did you take them to a shop and had them checked or did you just bolt on and play. I wont put them on until i have a cam to go with, so do i pick the heads first and match the cam or vice versa. If i buy heads first whats the key thing i should look for. Thanks for the info

98 camaro

scratch this....i'm into search mode so i've figured most of it out.....thanks ne ways