BG1tutu is worthwhile, but its not without its bugs even now.
It also allows you to start as classes you wouldn't normally be able to (as they were only introduced in BG2) like the Monk. Trust me, level 1 monks suck. They become untouchable and imblanced later on, but I played one through the whole of BG1 and he was utterly, utterly useless. It was only when I hit level 7-8 he could actually do anything, and that was toward the end of the game.
Try and pick up Kivan too - hes an Archer you can get pretty early on, and Archers are pretty imbalanced too. My first playthough I was an Archer and alongside Kivan we could drop almost whole parties before they'd even moved. Arrows of dispelling destroy Mages, if they're lucky enough to have got a protection spell off before they get an arrow in the forehead.
Ah, those were the days. I'm almost tempted to get them all installed again.