I have been posting here about my boost problem ('99 9-3 FPT), which was intermittent in the beginning, but then turned into being temperature related. At the end, I got more or less normal boost when engine was cold, but barely base boost when engine came hot. Problem also appeared sooner on hot days.
There were number of steps I took to diagnose the problem, with the help I got from this group, and problem was isolated to be either faulty BPC-valve or it's control. Saab dealer offered to diagnose the problem for $100 (or little over).
Well, instead of taking car to dealer I ordered new BPC-valve and installed that. I did that because based on WIS, blowing into C-hose should result air flow out from wastegate connection, and same should happen when blowing into R-hose. I was able to get some air through, but it was hard, and did not actually feel like WIS says 'free air flow'. So, I replaced BPC valve and bang, I got all the boost back right away! It cured the bloody thing!
I'm happy, happy, happy !!
BR:Z