I haven't done the pin mod, but the pot mod. There is overvoltage protection at 1.95volts which will sound an alarm and cause the mobo to not boot. There is a way to bypass it but you would need extreme cooling up there at them voltages anyway.
If you flash the TH7-II to the "77" BIOS that will give you up to 1.85v. If you wire wrap VID pins 1, 2, 3, and 4 then you'll have BIOS settings of up to 2.2v like JD says. Actual measured core voltage tends to be a little lower than what you set it at in the BIOS. Turbo used the 2.1v setting briefly to test his system and I used 2.05v briefly (1.95v actual with a spike up to 1.97v). See the below link for my overclocking adventure at those voltages. I do not recommend normal long term usage at those extreme voltages. CPU load temps get very warm and you run the risk of CPU damage from electromigration.