amo - brilliant avatar!
Reason for restart - it installs a new kernel extension, iPodDriver.kext. OS X allows dynamic loading and unloading of kernel extensions, (kextload and kextunload commands) so you really shouldn't need to do anything if the iPod driver isn't loaded when you install. If it is, you should be able to get away with unloading it, installing, and reloading it.
Thing is, Apple engineers seem too lazy to use the brilliant UNIX features S Jobs is so gung-ho about. This does not give anyone else any initiative to rise above "installing anything at all interesting means rebooting".
Sorry for the rant, it's a peeve of mine.