I think that turbos are fine only bad points are...
not easy to build...
and you always wan't more boost...guess that's all.
Why are they not easy to build?
All the information you could ever need is on the interweb, or from fellow members of the AOC.
You don't always want more boost, well I don't anyways.
When I first built the engine for the Almera the plan was to run it up to 30 psi, so that is still the aim.
If there is a restriction before that, then I will change the setup to suit.
The last time out, the fueling was an issue, because the injectors were at 100% duty cycle and the fuel pump was topped out due to the lack of flow because of the pressure requirements.
With the additional injector capacity now added, along with the 2nd fuel pump, I should be able to push it further now safely.
I may find that the exhaust system may become a restriction now and may have to step up to a 3.5" system, but we will see how things go.
All in all, even though the power may drop off, an average turbo charged engine will make more power & torque at all RPM points than an average NA engine.
P.S. I just compared my old N/A dyno' results to my latest results at 20 psi and the turbocharged engine is actualy making more power than the NA engine before the turbo has even spooled and that's with low comp pistons!