Boost leak is an issue of turbo cars, especially when chipped.
Boost leak may appear from turbo to y-pipe (#31 on dgrm)
or
from BPV (By Pass Valve) back to turbo - this rarely happens...
Here is a boost system diagram
You need to check (meaning remove and check):
Passenger side
#28 - lower hose (comes right after turbo)
#20 - lower intercooler hose
#26 - upper intercooler hose
Driver side
#27 - lower hose (comes right after turbo)
#19 - lower intercooler hose
#25 - upper intercooler hose
Dont believe it could happen?
here is what i found
NOTE: no need bumper removal! i was doing other stuff on car...
Upper
Lower
2nd lower hose