I put my boost gauge in last spring, there was a decent how-to of someone who installed their gauge in their vent, but I can't find it now to help you! I can by no means offer as in-depth help as a full how to, but I can tell you its not as hard as you might think. If you have ever installed a headunit its similar from the standpoint of taking apart interior panels and having to do some basic wiring. Here are some general steps:
1. Cut into the hose that comes off the top of your bpv and use your t-connector for your boost gauge hose. You mentioned doing this for an electronic boost gauge so you will need to mount the sending unit in the engine bay, a decent location is onto the battery box.
2. The sending unit can be powered straight from the battery, but also needs to communicate with the gauge in your car so you will have to run one wire through the firewall. There are a few different places to do this, I went with the same hole used for the hood release cable. To access this, you need to take off the main panel under the steering column which includes disconnecting the hood release cable to access the only screw needed to get the panel off (the rest are just clips)
3. The electronic wiring for the gauge like the power and lighting can be powered from tapping into your fuses which are underneath the glove box. The glove box will need to come out for this. Then the wires can run behind the center dash and will be under the steering column. I'm not sure where you mount your gauge but you will have to run the wires accordingly.
I know that was a pretty quick and vague overview, but I figured it would at least give you a gameplan for the project. If you have specific questions ill try to answer them and could maybe take some pictures this weekend but I can't promise, good luck!
