i have a intake, downpipe, catback and i also see 15-16 pounds in 3rd gear or higher. i think its normal, but it could be due to old main cats? i think it also depends on where your boost gauge is.

 

What kind of intake, downpipe and catback? We are talking about the RB dual tip here, which flows considerably less than say a Apexi N1 or something similar. Also, the boost gauge position shouldn't matter because it taps into manifold pressure which should be the same everywhere that gets pressurized. That is why you could have some of those vacuum lines switched up and know it.

As far as older cats is concerned, wouldnt they get clogged more as they get older? That would mean they become more restrictive which should limit the boost, not cause it to spike more. His problem is that his exhaust and intake are not restrictive enough to control the boost effectively.