Your first link doesn't have any sound. The MicroKorg wouldn't add much. Why not keep the Axiom?
The second track has the same Detroit chord sounds as explained here:
What's the better synth to make chords?
Any synth can do that. As for the Vengeance sounds - stacking and unison are the secret. A tutorial is of far more use than any synth - if you have more demo tracks I can write some for you.