Aye, an accurate boost gauge is always
the priority on a modded turbo motor.
If you were just getting one gauge after that then oil pressure, it is the quieckest way of spotting any immediate disasters which you can act upon before cooking the engine, and in a way it reflects the oil temp aswell because pressure is higher when cold and then comes down to normal when the oil is warm. If getting two gauges then bothoil pressure and temp would go well together.
Wouldn't really bother with water temp, it's not as critical as oil temp and you already have one in the dash.
I'd probably get the air/fuel ratio next, it's an easy way to make sure you're not running lean when giving it the boot, which should save you from potential meltdown.
If it was me, I'd get an intake temperature gauge before and exhaust gas temp gauge aswell. The intake temp is more critical for indicating potential detonation than the egt and you can use it as a marker for your limit on when you give it beans, much like the oil temp
In summary -
1 - boost
2 - oil pressure
3 - oil temp
4 - afr
5 - intake temp
6 - egt
7 - water temp
