boost gauge install

[GONEWALKABOUT]

Hey nooby question here, but im installing a mechanical boost gauge in my 07 spec b and iv plumbed into the bov line for now but was wondering what grommet people tapped into? Aim is to have it sitting in the cubby.
There seems to be one that sits top corner of the passenger side which holds nothing but seems to end in oblivion and one slightly lower central, holding all the wires?

Can put up pics tmro morning if needed. Thanks guys, had a look through searching but found not overly helpful threads.

[bigBADbenny]

There's a boost/vac line on the inlet mani passenger side near the ocv / oil filler area, mine is tee'd into that about 2 or 3" under the mani. There is a pic linked in the tune faq... Iirc...

https://m.flickr.com/#/photos/bigbadbenny/8370195850/