I just put an Intel T7600 2.33 ghz in my Mini 1.1 and it went pretty much without a hitch. I needed my son to hold a the backside of a pen I used to push on the pins that held the heatsink to the processor but if you make sure to take the time and have all you need before hand, like 4-40 3/4 inch long nylon screws and bolts, I didn't have to use, then you should be fine. This was the biggest upgrade I have ever attempted new CPU, max memory and 500 gig hard drive swap. I had changed things and installed cards in my old Sawtooth G4 but nothing as tight as the mini. After one day it runs at about 46 48 deg. C with fan always set to 2025 rpm. Smalll or no charge.
Ps I opened it up with a pizza cutter.
Sly