Hmm, went searching even more:
"Disable Vertex Buffer Objects=1"
This fixed the whole issue, except that the game still lags because these areas are graphically demanding by default, by this is fixable in the easiest way...
Btw another common issue I have(not only with KotOR, but other games) is that 2x AA makes a lot of colourful dots appear. Another game was HL2, which makes me believe it has something to do with OpenGL, both using the same API if I recall correctly.
But this is nothing to be concenrned since I don't run it without any AA
Too laggy if I do.
Thanks for the support, the walktrough here is the best I've found. I love this site
