Re: JTD Boost gauge ??
No, you have to drill and tap (or screw in a brass connector, it will cut ally, but you would be better to tap it) as there is nothing that provides a boost pressure feed.
If you can find an excuse to remove the inlet manifold then do so, I am currently looking into the restrictions of the butterfly which reduces to 2" before the manifold and may well cut out and enlarge to 2.5" for bettter flow.
It is better to see pressure at the inlet rather than pressure before a possible restriction.