Intake won't make a lot of difference alone, but a good SRI and larger diameter smoother flowing TIP to replace the convoluted Mazda one will help it breath better and you may gain a few Kw and a smoother run at higher registers. A decent DP can add up to 20Kw if done right, with possible other exhaust enhancements, but needs research to get the best setup.
I have no idea what the other cars are that you refer to with the gimick-speak, or their power outputs, driver skills, what gear they are in, etc, etc.......so comparisons are impossible. Also just because his turbo is running the same pressure doesn't mean it is running the same volume.
BTW, I think you are referring to BARS of boost, not BARG. Barge is a riced-up Honda Accord. ;-)
Last comment: The MPS (3 or 6) was never intended to be a drag car, it is a high performance tourer. If that is what you intend to use it for, then you need to pay for decent mods to meet that end, not just a DP and SRI. In that realm, the sky is the limit for mods, and hence $$$$.
CP_e Standback & PNP; CP_e 3" SS Downpipe; Corksport FMIC with Top-mount K&N filter & OEM Ram CAI; Turbosmart BOV; Dashhawk; Prosport Boost Guage; JBR solid shift bushes; DBA 4000 Wiper-Slot front rotors; Hawk Ferro-Carbon HPS Street front brake pads (@ 69,000km); Sumitomo HTRZIII's in 225/45 x 18