Re: guage drilling and tapping
it's pretty easy...I did the stock VA on my Xtra. The tricky part is drilling high enough, not to cut into the reg/xchamber threads area and back far enough not to interfere with the LPC threads.
*Spring-loaded punch (to set the hole so the bit doesn't skip across the surface)
*Drill and bit
*1/8" NPT threaded tap (package recomends bit size)
Use the punch to dimple the aluminum. Drill it. Tap it by hand turning the tap. Insert tap into hole...press down with moderate pressure and turn 1/4 turn. Back it out. Turn 1/4 + 1/4 turn, then back it out. Then turn 1/4 + 1/4 + 1/4 turn and back it out.....until you have tapped the hole to the widest part of the tap itself.
The reason you "back it out" is that the tap cuts the thread and creates metal slivers. By backing the tap out, the slivers are cut away and are allowed to fall into the grooves on the tap...removing them from the hole you are making. GO SLOW AND TAKE YOUR TIME
teflon tape the gauge and install.