Why wouldn't SP2 screw up the machine is a better question. M$ have been going on and on about SP2 and it is a lot more than just and normal service pack like those for win2k. It is going to change core functions of the OS and how they work.

While i agree the shell is seperate, that doesn't mean it won't impact LS. A web browser should be independant of the OS, but that doesn't stop IE being a "core" function of everything in Windows from the file explorer to calculator ;)