I am wondering if perhaps there is any other intervening reason as to why the fruity N64s had success, while the gray ones did not. Is there a way of checking the CPU revision between the models? Also, I noticed that at least a couple of people mentioned that their flaky N64 mods were done with switches, to return the console to its standard speeds--these folks had gray N64s (I think), but I wondered later if perhaps the reason their games had a lockup tendency after the mod were in fact due to the switch, or to a little sloppy work because of the switch?
That last bit really interests me, as I am thinking about doing this mod, and I would definitely want to switch it in case any given game seemed to run too fast.