TDIMeister
Phd of TDIClub Enthusiast, Moderator at Large
On what would he be basing that on other than what we reads from the dyno plot (which tells you pretty much squat about how the turbos are working)? If the HP (high pressure) stage is restrictive, it's most likely so on the hot side, not the cold, and you can get around it partially by bypassing part of the exhaust gas flow around it with a wastegate and dumping it into the turbine inlet of the larger LP (low-pressure) stage. That is, unless your LP turbo is already maxed, which is what I believe is more likely the case; then, the aforementioned bypassing won't help you much at all.When it was getting Dyno'd the tuner said that the HP was maxed out and that it was going to pop from the pressure. Are you sure?
But of course, you won't know that just from a dyno plot, but you'd need at the absolute minimum to measure exhaust manifold pressure and EGT while performing the runs, and even better would be to simultaneously measure interstage pressure and temperature and turbo shaft RPMs.
I repeat, a dyno plot alone will not tell you what you need to know. I did my MSME in two-stage turbocharging.