Quick Autometer question here...
It's also illegal to run a mechanical fuel pressure gage on the street (i.e. no fuel allowed in the drivers compartment) unless you're running a FPG with an isolator - but by that time you might as well use the electrical version.
Seen some run a mechanical nitrous gage - but personally I would go with electrical on that too.
Fuel pressure and nitrous pressure electrical gages are considerably more $$ than their mechanical counterparts. Every other gage price is comparable.







