Hey there, I'm just about to purchase a few thing but I want to get it right on my first go, I have a 98 v6 ecotec vt factory manual commodore but before I had purchased it, it has had an engine swap with a vx ecotec and I'm struggling to figure out what

You would need to find out if your current PCM has the ability to accept a memcal or not. If it does, then it would still have a VT specific computer. Otherwise it would likely be a VX specific one. To be 100% sure though we can advise accordingly if you can let us know of the service number labeled on the outside of the PCM.