Ya snoop helped out on it's going down, Bert McCracken helped on Faint and Jonathan Davis helped on One Step Closer...i think snoop added some extra lyrics too...but i'm not sure about that
bert and johnathan came out at the 2 shows i went to but snoop didnt come out either of those times for any song
Apparently Snoop would come out at some shows on It's Goin Down and rap one of the verses to Gin and Juice over the It's Goin Down music. But from what I've heard, his mic didn't work a few times he did it.
All three came out at the Detroit show! Except for Snoop maybe...I think it was just DJ Z-Trip and Ivan the Urban Action Figure that came out for the medley.