There's a thread about this on SDN, but I thought it might as well be posted here as well: http://www.deadlystream.com/forumdisplay.php?f=123
I installed it about a week ago, and I've played the game for a bit - I've restarted, because I downloaded the M4-78 Droid Planet restoration too and I need to start a new game, but I got up to Nar Shadaa at least on my first play through and I can tell you what I've noticed so far has been pretty good. Little things, extra dialogue and extra scenes that do a HELL of a lot to connect scenes that weren't in the original game.
If you like KotOR 2 TSL then you'll want to give this mod a try.