You would be hard put to do any damage to the 1/2 drive 3/4" plug between the MAP sensor and the fuel filter. If you get it out, you will have to go to the hardware store to get a 3/4 npt to 1/4 npt bushing/reducer - stainless or galvanized.
The boost bolt on the intake manifold would be my first choice, 3/4 plug the second, intake third. I would like to see before and after (intercooler) readings with the boost tapping the turbo.
The intake horn is about 5/16" thick, fairly soft aluminum. Comes off in 5 minutes with a 10mm socket on the mounting bolts (take the oil dipstick bolt out FIRST!) and an 11mm deep well for the boot clamp. BE NUMBER ONE CAREFUL when you lift the horn off the grid heater assembly. The gasket likes to stick to either part, sometimes both so you do not want to damage it. Decide where you will tap into your horn BEFORE you remove it. I say this because if you decided to put it on the bottom side for the clean look, you will need to mark where so you don't have space occupation issues with your boost tap and the plastic cover above the pump.
Use a center punch to dent the mounting point where you are going to drill. If you have a drill press, clamp your horn in position and drill away. Without removing the horn from the press, switch out the drill bit with the correct NPT tap and use the press BY HAND to tap the hole. Either use the chuck key to turn the tap, or a socket on the pulley on top. Makes it a lot easier to get a good straight tap. Make sure to use some grease or oil to lube up the tap while you are doing this, makes for much cleaner threads in the aluminum.