what bits are involved

ive got a rough idea but when it comes to the loom does it need to be 2wd or 4wd one. same applies to the ecu L6 L8 etc etc. do certain ecu work only with certain looms

next part is the whole timing issue. ive seen some cars run a modified rst/cossie distrubter while others run it similiar to the efi set up. what CPS is needed presummed to be the best?

im total lost on whats needed

cheers