The Impreza has virtually no gauges to let you know how the cars engine is running. The only standard ones worth mentioning are the coolant temperature, low oil warning light and the Check Engine Light (CEL). The coolant is a decent indication to let you know if the car has warmed-up before driving hard, but the other warning lights will probably only be shown once damage has occurred or at least something has failed.

There's obviously loads of information you could want to know about the engine, but I don't want my car looking like the cockpit of a F16, so I decided to stick with Oil Temperature and Oil Pressure.

Low Oil Pressure is a bad thing, so worth knowing before the built-in one illuminates after you've broken your engine. The warning light only activates at a very low pressure (10psi apparently) and with the idle being around 30psi, this is not a good thing. Low Oil Temp means takes things easy and very high temps means back off before something expensive melts.

I did consider going for some matching Autometer gauges, but that would mean 3 gauges and the only place to mount all those would be a centre pod (replacing the cubby hole on top of the dash) or on the A-pillar (a bit OTT for me). Then I saw some SPA dual gauges and I opted for one of their combined Oil Temp/Pressure digital gauges. These are electrical gauges that uses senders to monitor the oil temp & pressure in the engine bay and pass the signal back to the gauge along a single wire. Mechanical gauges actually take readings from inside the gauge itself and running pipes with hot, pressurised oil into the cabin isn't a good idea in my books.

The SPA kit, includes the gauge itself, a replacement Oil Pressure sender and an Oil Temp probe. Unlike the mechanical boost gauge the electronic gauges use senders/probes to read the appropriate readings direct from the source. I didn't like the idea of a mechanical oil gauge which needs hot oil running inside the cabin.