I salvaged two IOpeners thus far.. the first had a fried mosfet from me experimenting with bridging the IO to a PC through the IDE bus so I could have the PC directly manipulate the sandisk. (Seemed like a good idea at the time.. hmm..)
The second, repaired fairly recently, had a pair of pulled traces from a failed attempt to replace the BIOS Socket. Man oh man, do I hate repairing pulled traces.. Spent an entire afternoon repairing the damage with a handy soldering iron, good tweeers, and some nail polish for quick n' easy insulation and glue. Would've been easier if I had a lab dedicated to this kind of board work. Ah well. This machine is now being used for the floppy-drive work.. so at least I feel better knowing all that work wasn't for nothing.
I'm not volunteering.. just mentioning some of the troublesome hardware mods I've encountered. Sure would hate to see what "real" technicians see on a daily basis.
Anyways.. my suggestion.. if you're going to do the CPU upgrade, go for the full boat. Split-Voltage, CPU Switches, Power-Supply mod (piggybacked resistor), and VCore tuning pot. Then you'll have all the options you want. Search for posts by ASPGuy for a parts list to estimate cost for parts.