[naturalextraction]

First off, Christ, I agree and my opinion is that, depending on what your goals are with any engine, static compression is just a baseline.
Pgfpro, I'm glad I could help. In today's world of I.C.E.'s making any marked improvement is difficult as they have been tested and reformed to death. There's only so much you can do with this currently inefficient design. So what small improvements get made along the way and are always welcomed.
So welcome to the "high performance high mileage club". I don't see it any other way. As you may have seen on my site the 72 Duster prototype engine, in which I've done the same in regards to turbo frame enlargement to get higher performance.
Making changes of course is critical. Knowing what your compressors output will be at lower rpm, your cruise and what it will need for input on the turbine side is significant to maintain your optimum lean burn numbers you have now. This may also be compensated or regulated by compressor and or turbine trim, A/R ratio, etc. That's why I asked if you had a divided inlet on the turbine side. It may provide a little more turbine spin at lower rpms. Particularly if you feel your at your optimal combinations. I've made my own device that helps do that while not loosing my mid and higher exhaust output efficiencies to the turbine wheel. If you find that you run into a low rpm issue due to compressor out put being to low, I will share that information with you. A divided inlet doesn't completely cure that thus why I devised this inlet device.
Sometimes you need the larger turbo combinations to get that extra performance, especially if you want to increase pressure, but you may sacrifice at cruise. Again I don't know what the specific differences are from your previous turbo to this one. My rambling may be a muet point as your combination may be just fine!
I'm glad to see you do the home work and I think you have something valid in your work! KUDOS!