Basic gauge questions. (kinda long)

[chris91LX]

I'm looking at putting in several gauges, but I don't want them obvious, trying to keep it low profile. The only fuel pressure gauge I've seen that you can mount inside your car instead of on the cowl or in the engine compartment is an electric kit that's three times the price. I want my gauges (fuel pressure, oil pressure, oil temp, water temp, maybe a Tach and one or two more?) inside the car, like in the vent cage and/or a custom setup beneath the radio. My questions are:
1. Do I need to use electric Gauges for this setup?
2. What's the difference between electric and mechanical gauges from an accuracy and ease of installation standpoint?
Thanks in advance for any info guys....

------------------
91 LX 5.0
Z t-5, 3:73 gear, Vortech 73mm Mass Air, Accufab 65mm TB, BBK underdrives, Crane HI-6S Ignition, BBK unequal length headers, Bassani x pipe, 2.5" Dynomax Super Turbo cat back, Kenny Brown Super Subs, Factory Five Control Arms, Mac cold air kit and more to come!