I don't understand the need for the boost gauge
since the boost is limited with pulley size you shouldn't be able to overboost or anything like in turbocharged cars, am I missing something? as opposed to turbocharged cars boost level should be pretty consistent and shouldn't be affected by the temperature etc..
as long as you are hitting the target boost (which can be seen with a simple Torque app) I think you should be fine .. if the accuracy of the boost readings via OBS is questionable, I don't know