In all honesty, I think a very, very small percentage of widely available leaked tracks are unaltered, especially in this day and age of mp3s and downgrading (due to compression and stuff). The first two bootlegs I bought (East 2 West and some other one, both of which I still have, and were actually from someone on this board, haha) in early 1997 were ridiculously downgraded, but even in these versions I hear random things (background vocals, adlibs, ambient sounds) that I don't really hear in most of the mp3s of the same songs nowadays, even though they are in better quality. I forgot who I bought my second set of bootlegs from (Makaveli II, Makaveli III, Makaveli IV, Heaven Has a Ghetto, and a few others), but they sounded a lot sharper and some had the "mothafuckin' express" tags on them, which I believe Dante said were "ripped" from a cassette. (Feel free to correct me if my memory isn't totally correct.) The bootlegs started to have better sound quality through 1997, and with the rising popularity of mp3s at that time they got into the hands of many more people who fucked with them and remastered the shit out of them. So more than likely, the individuals (with direct connections to people who have had access to Death Row's vaults) who first started leaking the songs probably have almost everything that we have in CDQ final mix form.