...without them, it won't work correctly and although drivers are usually available, with SONY, some have been hard to find.

Ideally, XP should be installed first on the drive, then Vista can be installed. If you're looking to dual-boot XP after Vista is already installed, I recommend getting a second hard drive, unplug the first, then install XP on the second drive.. There have been other threads attempting to do what you suggest. Most have had poor luck doing so.

Hope this helps.