Not sure what you mean by that last question... do you mean if the Sarevok fight gets harder if you have TOTSC installed? If so, I don't think so.
As for importing a BG1/TOTSC character into BG2:
You need to export the character from your game first, of course. Then take the character file and put it in your BG2 folder, in a folder called characters. Now, when you create a new game in BG2 and go to Character Creation, it should be available under "Import"
My memory's a bit rusty, it's been ages since I played, but this sounds about right
Good luck!! [img]graemlins/happywave.gif[/img]