I'm running the same setup as you... 2GB ballistix with a 3800+.

To answer some of your questions, you're safe up to 1.6v on air cooling. You probably won't be able to take your chip that far because load temps would be in the mid 60's... my max voltage (for now) is around 1.52- even then my temps are 55-57. BTW I hit 2.65ghz at 1.52v, not good, not bad.

BUT the one way to take your chip voltage farther with better temps is to throw your warranty out the window, risk the life if your chip, and remove the IHS. I'm not gonna say any more about that, reason being I don't want to be responsible if you kill your chip. Though if you're interested ask