I found that guide, but it says that if you go dark side then you stay on malachor and become a sith lords, it also says you can let Kreia live, what is that about.
Apparently the "not blowing up of Malachor" counts as the first (become Sith Lord). You also get your own PC on the front menu of KOTOR2.
Kreia MUST Die..., so no idea what that's about
I can't get the requird influence with T3, so what is on his messages from bastila and carth.
Influence is not needed. The req. is a few points in repair And (most importantly) 15 of INT