Mine aren't 100% installed yet... but they are AutoMeter electric gauges I scored offa ebay for $60 shipped (both gauges). Just need sending units now; stock "Oh Crap" lights suck too... they always come on when it's almost too late.
They snugly fit in the vent holes with a little trimming of the metal reinforcement part of the dash. I blocked the top of the vent box with some random plastic while the dash was apart. When these get installed I've got some heat shield stuff to help protect the gauges from the heater core temps. I never used the "vent" setting so I figured this is a good place for gauges; I'm more of a "heater" or "defrost" kinda guy.