I am putting a gauge on my 88 vert conv. that I turboed and I like the accuracy of a boost only gauge that goes to 15... but will the vacuum readings show engine wear eventually? What are the typical vacuum readings for a turbo 13B and will they weaken eventually showing seal wear or not?

 

location and size and color for gauge... my car has the grey interior and I was leaning towards a white face cuz they read easier but i'm thinking black now to not stick out.
Also, where is the best place to tuck it... I have the original radio in and I think it will be the only extra gauge I put in. I'm sure some of yu guys have solved this neatly.. I don't want a pod anywhere.
thanks