Yes you are correct and have spliced into the right line. Before I did the boost adjustment, I was running 8-9 psi max boost, at about 3000 rpm under full acceleration. Something you will want to do is to check boost on BOTH sides of the overboost sensor. What you and I have right now is a reading of intake manifold pressure. The ALDA may not be "seeing" this exact amount of pressure due to a clogged overboost sensor. Either way, it's a good idea to give the overboost sensor and a good cleaning.