Today I installed a pressure sensor in place of my bank 2 O2 sensor.
I was surprised see a peak of 15psi in the exhaust with a peak boost of 21.
This is with a tune, meth, and 3" catless downpipes.
The rest of the exhaust is stock.
I think I will be installing a 2.5" X-pipe in place of my 3rd cat to lower this back pressure for hopefully a little more power.