I had some gauges from my old car and didn't want to spend any money on new one. For coolant tempature I have a Autometer gauge with the sensor that mounts on the side of the coolant filler neck. That is probably not the best place to put it, but it was convient.
For Boost I have the digital gauges from my Apex-I Super AVC-R and I also have mounted on my dual gauge pod a HKS unit that was off my Mazda RX-7 Turbo II.
There is actually a Fuel Pressure Gauge that is mounted behind the bottom HKS Boost Gauge. The make for that is also a Autometer. I chose the Autometer unit because of it's simplicity for install. I just had to hook up one sensor to my SX Fuel Pressure Regulator, run a signal wire from the sensor and hook up power, ground and the light wire. Took all of about 30 minutes to hook up.