Boost question

[txjeep]

Hi all.

Background:
I have a 2003 Excursion with 7.3. I bought it out of state from a dealer and had it shipped to me. Little did I know that it had a 38r in it, a Banks turbo back exhaust, and Banks chip as well. It also has a Banks tranny controller or something underneath, and a cold air intake with a K&N on it. Not a Banks fan, but it really performs well as it is, and the exhaust is pretty nice. However, I am planning to begin towing a 36' trailer soon (8500 Lb empty), and I am thinking the Banks chip is not what I need. I was considering the Phoenix chip with all three tow programs, plus the 80DD, 100 perf, and whisper modes.

Now to my boost question. I recently installed the pyro and boost gauges. The gauges indicated that I had a pretty major boost leak. Found one of the boots on the intake plenum was half way off on the back side where you could not see it. I fixed it and everything seems to run much better (and quieter) now. However, now my boost climbs rapidly and hits a brick wall at 20-21 psi. It does not act like a leak, but like something is limiting my boost. I checked the up-pipes and all the boots and everything looks tight and clean. The boost gauge is installed in an AIH delete plug using compression fittings, and does not appear to be leaking either. I disconnected the wastegate (a Banks BigHead if that makes a difference) and plugged the red line already, so I am thinking it must be defueling, which is what it feels like. If the computer on the truck is limiting the boost pressure, my question is if the Phoenix chip will allow my boost pressure to climb to higher levels without some sort of boost fooler. I have the 38r, so I don't think I need to worry about messing up the turbo. I assume I have stock injectors, but I honestly don't know. I can floor it and EGTs top out around 1100. With the boost leak it would hit 1200 without even trying.

One more thing, with the 38r, do I have to pay for the higher priced "heavy mods" chip? Not sure if the 38r qualifies as "large turbo" or not.

Thanks!