I have the digital inverter so I can get 4-5 shades of blue and of green. On the brightest setting they are too bright for me. I usually keep it on the second brightest and it isn't a problem at all. You get a reflection of the gauges in the drivers side window or windshield though (which isn't too bad as it isn't in the line of sight.
Well, they'll fit in the GT, but I don't think they'll work correctly.
Actually, the Indiglo ones might work because, like on mine, no stock lighting is used at all (no light for the odometer because that's how I hooked it up). I'm not sure about the Reverse Indiglo ones though as I believe they use the stock lighting.
I'd be happy with the GT gauges if I were you.