im looking at getting an aftermarket oil psi and fuel psi guage, what are the pros and cons of an electric or mechanical guage ?

 

You will have a hard time finding any electrical units as most fuel pressure and oil pressure units are mechanical. However if you did, the electrical guages are usually much more expensive, however they are also much more accurate, and sometimes have nice features such as recalling max pressure, and some even have warning lights you can preset to a certain pressure level warning you before you reached a critical pressure level.

 

oh cause ive always heard that mechanical were more accurate, but yes i have noticed electrical were more expensive

 

Electronic fuel pressure gauges are fairly common. AutoMeter has been making them for at least 10 years. They have both high cost, full-sweep (270*) and low cost 90* sweep electronic units. Take a look at the current online AutoMeter catalog.

You can't install a mechanical fuel pressure gauge in the passenger compartment, unless you use a high pressure isolator at the firewall, to prevent fuel from entering the passenger compartment. Keeping the isolated side of the system filled with glycol is a major PITA, leading to bad pressure readings. I had a mechanical gauge for a while, and the AutoMeter high pressure isolator failed, and allowed fuel into the line to the gauge. I would stronlgy recommend not using a mechanical fuel pressure gauge inside the car. If you have to use one, mount it on the hood,

I honestly do not believe you can claim electronic or mechanical are more accurate. I've seen more electronics with problems, though. I run a mechanical oil pressure gauge, mechanical nitrous pressure gauge (with flow restrictor), electronic fuel pressure, electronic oil temp and electronic tranny temp.