If you HAD to have one gauge: Fuel Pressure A good fuel pressure gauge will alert you to problems before a wideband could thus giving you an extra second or two to shut down the motor.

Vac/Boost gauge is also a good one to have for a number of reasons. When you get down to it, unless you are actively tuning or running a system that auto-tunes, a wideband gauge is nothing but a fancy light show. If you can't live without one though then get Innovate's gauge kits. At least then you'll have an accurate wideband and some datalogging capability.

 

BINGO! You lose fuel pressure in a boosted engine bad thing happen quickly. A/F ratio is controlled by the computer. Noticing a drop in fuel pressure while in boost will give you a chance to shut down quickly and hopefully keep from doing major damage.

And BTW, my installer recommended boost and fuel pressure.

 

correct on the wideband. knowing your a/f ratio at wot is very important.