I have a gig in a few days with the 57SL. I use my external Serato setup at home with the latest software update 1.8.1. Would the mixer be compatible with my computer and it's software (Macbook), or do I need to install a special version for the 57SL?

Also, any tips regarding a first time gig with the 57SL that may be handy/useful would be VERY MUCH appreciated! :]

Thank you for any help,

Nope! Just plug and play.

Another question regarding the 57SL. How come Serato only works from the PGM INPUT 1, and PGM INPUT 3?...clicking the dial to digital deck 1 or 2 with the CDJ's connected to either input 2 and 4 will not read the time-coded CD. Very weird?

Inputs 1 & 3 are Digital Inputs. 2 & 4 are analog "through" inputs.

Just to clarify Dj Woody, I found out on the Serato forums that the digital inputs can be routed in the 'hardware' tab in the setup screen, just a heads up if you were not aware!