i don't know about autogauge, a local
shop sells them they seemed a bit ... "cheap" .. i use VDO in my car they are very good quality. I got mine from 42 Draft Designs, though - maybe a bit expensive on shipping for you. I just recieved my dual pod from Nomad racing, good finish, but im still windering
how to best fit it as there are no clips.
On a 1.8T its simple, but for a TDi as Sisson said, you will have to drill the IC pipe and use a barb fitting. Install as close to the intake as possible for most accurate reading.
Also wire the illumination to the dash brightness switch, not ACC, so the gauge dims with the rest of the dash
good luck!