Sorry my question was a bit unclear.
I meant if going a full standalone ECU (e.g, Haltech) can someone avoid buying a front cut (and hence complete wiring)?
As a front cut is 6k+ but a 4G63 long block is 2k or less.
In this instance the transmission won't be used, the turbo manifold needs to be customized, the intercooler piping needs changes, and if not using the stock ECU what else would be needed from the front cut other than engine mounts?
I know it'd be a lot tough to swap but maybe more cost effective too?
It's entirely possible to use a 4g15 ECU and reflash it to suit the 4g63. You would need to add a couple wires for the knock sensor, and change one or two other pins, but we're talking less than about 3hours of work of wiring. Of course you need to have the knowledge and skill to do so for the reflashing, but yeah