I'm unable to verify this, but I believe this is the first circulating recording of Mike's Song where Trey and Mike are jumping on trampolines during the jam. In previous versions, Trey plays the "Stranglehold" riff in unison with Mike, but 3/4/89 is the first time you hear Trey start his solo by sustaining one long note with feedback. To my ears, that's an indicator that he was jumping on trampolines (it wasn't until 1992 that Trey became confident in his ability to solo while jumping). This tradition continued, as far as I know, until 12/31/94, and only occasionally after (e.g. 11/15/96).