The difference between mechanical and electrical is that on a mechanical, the force through the engine that you are actually trying to measure gets read on the gauge. And mechanical is done through electricity (obbviously) For example...A mechanical boost gauge is read through the force going through the tube, and making the needle move. A electronic Pyro is read through a sensor in the manifold, and then sends a signal to the gauge. I am a big fan a autometer, simply because in this case, I am a bit of a fashion over function kinda guy in this. I am close enough I figure so i am not worried about it. Many people also like the Dripricol's and isspro's becasuse they are built great and also have a stock look and match the factory dash fairly decent.
Here are my Ultra Lite II's