I took the PTO cover off the drivers side of my G56. Genos should have a fitting whereby you can drill a hole in about the center of the PTO plate you removed. This hole needs to accommodate the aforementioned fitting that steel and is solid on the outside and threaded for standard 1/8 npt which just happens to be what your temp probe is. Next, yes manifold pressure is manifold pressure. Someone told me the inlet horn is already tapped on the new trucks. If it isn't then you can get a hollow bolt from Genos that will replace you stock intake manifold bolt. This bolt will accommodate your hose fitting for boost pressure. Most of the boost kits you can get from Genos come with this bolt included free. If not they sell them for around $7 id I can remember correctly. Be sure to follow instructions and don't torque the bolt more than what they list. I strongly urge you to get an exhaust gas temperature gauge.
Have fun and enjoy your truck...