Performance mods?

When I take the time or money to work on my car, I do a good job. I don't slack, if there is a missing screw i have to go get another and put it in, i dont care if that screw holds on my door panel.. Its annoying to half ass my own car, I'd rather KNOW that my heads are in good shape than just throw any used motor in there. What are the pros and cons of slappin on some l67 heads with a gtp pcm? and a quick question on the side, this may sound dumb, but I want to verify it before i live by it. Does a PCM need to sit in a plastic box? When I did the cold air intake custom, my pcm had no where to go. So I used some zip ties and put some mouse pads between the pcm and my frame for now, I didn't want it to ground itself by some freak accident on my car. I've been busting my ass making this custom PCM box, and I want to know if its worth it? Its not even half done. Or if anyone knows a place I can buy a box for cheap? If its even necessary?

doesnt really matter.

I suggest buying headers and a tuner. Start learning how to tune on your N/A before you start getting into forced induction. Then gather all your parts you want for the build, then top swap/engine replacement all at once. Then you already have headers and may know how to tune.

would it be possible to learn how to tune and eventually tune my pcm to work with the L67 head with a m90 supercharger, and save some money when I get those parts by tuning my own pcm? and how do you suggest I hold it in there? its just sitting on my frame at the moment..

Mine's never gone anywhere in either car...and they just sit there as well.