Here's another option. Restore the intake to normal temporarily. Put the stock air box and inlet pipe back on and reset the ECU. Drive it a bit. If you are still getting the boost swings, then you know you have a leak in the plumbing somewhere, either a boost tube, a vacuum line or a problem with the boost control solenoid.
I gather you are not throwing any check engine light codes.
Did you properly install your boost gauge? Was it working fine before the intake mod, or did you install it at the same time? Maybe you do not have it connected properly, or there is a leak in the line to it?
Since the SRI and TIP are your only mods, you should be able to return everything to normal and take it to the dealer and get it diagnoses and fixed under warranty if it still does the same thing.