The A/D conversion for the boost gauge happens right at the sensor pickup mounted to the intake manifold. The connector is high quality and has a rubber gasket to keep the elements out.
The thermocouple wire for the EGT gauge is long enough to route through the firewall and well into the passenger compartment. There it plugs into a small black box that does the A/D conversion before the signal runs into the back of the gauge.
The SPA gauges are expensive, but also use first class quality components with tons of features (too many?) that can make them difficult for the average user to setup. You can order with a white or black gauge face, and black or chrome bezel. You can select the backlight color (red, green, or none) and adjust the backlight brightness level. Gauge hookup is very easy requiring only two wires, +12V DC and ground. EGT gauge has a very fast response time taking any guesswork out of the exact temperature you are running right at the moment. Plus you can get the peak values for both boost and EGT with the push of a button. You can change the units the gauge displays from PSI to bar, and °F to °C if you choose. You can also program high limits to illuminate special LED’s or optional relays for over boost, or over temperature conditions.