I don't know jack about computers, but I do know that I have XP. I got SP2 on a CD. I made sure that I had a clean PC(adaware, spybot), updated my anti-virus program, ran a scan, it was clean. Defragged my C drive, made a restore point, rebooted my PC, then installed SP2. It took about 20 minutes, and I don't see any problems in the 3 weeks I've used it. I have no idea what slipstream is.
The only question I have is now when I go to some sites the videos load in my browser, it used to be that ms player would pop up and the video would play there. When I checked the properties is said it was media player 9, my default player is ms player6. I don't like that, but I don't know if it's due to SP2 or not. This happens in Firefox.
I say install it if you don't have a bunch of Kazaa, bonzoi buddy, coolwebsearch-related spyware and such. Otherwise get rid of that stuff first.
HTH