I think I might have very slight leak with my intecooler/bov/hoses and I'm having a heck of time tracking it down. I'm seeing varied boost(+/- 3psi) in the same gear/load/rpms.
It was suggested on NASIOC to rig up something like this:
Basically you make some sort of adapter with an air nipple that fits tight (with a clamp) over the intake of the turbo, then pump in air from your standard air compressor, being careful not to overboost over say 15psi!
If there's a leak you'll find it real quick. It's amazing where an IC system can leak, vaccum hoses, couplers, endtanks, flanges, etc...
Here's a pic of an adapter for an Audi S4 to give you a general idea. I have a similar one for my dsm that fits the rex turbo.
Another question I have is if there is an available part to replace the fragile BOV gasket that is stuck on the OE IC? Let me know as I might start with replacing that as I slightly damaged mine which might be causing the slight leak.