There is absolutely no need for a new partition I actually recommend the opposite, never have more than one partition on a drive, buy another drive if you want to see an improvement in performance, making another partition on a drive will generally decrease performance.
Just install PFE and FDC to their own custom location, something like C:\PFE or D:\FDC etc would do nicely and the Windows 7 nanny state security features should leave you alone. You absolutely must do this when installing FSX and FS2004 too otherwise you are asking for problems when working with third party apps like FDC, PFE.