[H] Win7 Ultimate to Home Premium?

[Steve Tomporowski]

On one computer, I currently have a *censored* copy of Win7 Ultimate.  I 
am going legal now and bought a copy of Home Premium, since I don't need 
Ultimate.  Is there a way to downgrade without having to do a clean 
install and lose a week re-installing all the tweaks and programs?  I'll 
bought the OEM System Builder Pack (3 Licenses) from Newegg.  So if 
installing that on a computer requires something special, I'd be eager 
to hear.

Thanks much....Steve