Just get the cheapest if your gonna change stuff out for loads of uprated parts, my advice is find a good healthy lump, non abused - loads of 20vts out their bit loads are in a sh!t state
K04 set up would work on any and is good in a mk2 / mk3
Bam / AMK etc are my personal faves but are ££££££ for a genuine good example
Aum is fine, can always do the K04 upgrade easily