The OP has a 2000 GTP.
So the electrical is fine as is.
The PCM just needs to know about the injectors, and bump the idle speed to help out the timing chain. Also have the P0300 turned off. But if the OP's PCM was already tuned for that, it'll likely be fine.
Head studs are reusable. Head bolts are not.
L36 head gaskets are cheaper than L67. Couldn't tell you why, all I can tell you is that's what I used every time. Felpro MS98014T was the LIM gasket kit I used. Steel former, pretty nice kit.
The machine shop can likely check the spring rate of the valve springs you have.
