Hello all! So Im feeling a little stumped. And since I believe my issue may be with turbo components, I figured I get all the advice I can first before digging in to my engine bay again, and especially my wallet. 
2006 Mazdaspeed 6, 168,000 miles on the ODO. My issue is that I feel like I am not quite getting as much boost pressure above 3100 rpms as it use to. Several months ago, the boost coming on was fairly noticeable, but now I don't think I am feeling it at all. As far as I know, the engine sounds and feels fine. It climbs through the revs consistently, but again there's not much boost, if at all. No smoke out the exhaust. No questionable exhaust odors. No odd sounds. No codes, no misfires. Over all the car is fine. It has a slight oil burning tendency, but it's my understanding based on discussions and findings in the Mazdaspeed community that burning oil is typical for these platforms, especially at high mileage. I do have an Oil Catch Can installed, and it looks to be doing its intended job with no PCV leaks. I also have the secondary catalytic converter swapped out for a straight pipe, leaving the stock catted downpipe still installed so it's not a full straight pipe. What do you guys think my issue could be? Could it be the wastegate actuator solenoid? The wastegate itself being stuck open? If so, how do I perform this kind of inspection myself? 
Thank you for bearing with my many questions, and for your time. I greatly appreciate it.

-Josh