I also have the 4 disk set and keep installing the game on each new computer I get. I was amazed how much it would cost to replace my set...if I had to.
Have all the patches and mods (Official and fan made) on a backup disk to restall afterwards. The "Spellhold Studios" PS:T forums has a large dedicated group of PS:T modders who work to fix any bugs Black Isle may have missed or cut before release. Also any improvements and/or tweaks so the game can still be played. Including one that increases resolution.