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93 octane gasoline is good for at least 340lb-ft and 410rwhp for a 2.0L
Even using 17 year old turbo tech such as 50-trim and 60trim style journal bearing $300 rebuild pieces of shit turbo can make those numbers.
A 50 trim will give 300lb-ft of torque around 4000rpm easily and top out 400rwhp no issues. And a turbo shop will give you that wheel free because nobody wants it since 15+ years has gone by. And this is 93 octane fuel gasoline only.
For alcohol the minimum power is 500rwhp otherwise you would just be using gasoline. And there is no reason to see a gasoline 2L making less than 400rwhp. It doesn't make sense from a promotional point of view. At low power, alcohol is merely a clean burning fuel and a safety margin, not a performance enhancer.
Turbos have not gotten much more efficient. In the old days they are (64 to 67% baseline) up to 74% to 76% efficient. Now they are up to 75 to 76% efficient. They gained maybe 1-2% over the last 10 years or so. The big difference in turbos now isn't efficiency it is capability, metallurgy, design process, material science, etc... engineering and materials properties have increased their flow rate while maintaining a low wheel mass which allows them to support more power and spool more quickly- but it does not improve their efficiency as compressor adiabatics for impeller style pumps impart heating of the air due to friction which cannot be negated in the design of the turbo or compressor but rather has to do with the air interacting with itself and surroundings under the circumstances of compression.
In turbo decision it is ultimately the application which calls for flow rate (mass rate) throughput and adiabatic targets. For example in a drag racing app with nitrous/2-step if the target power is say 1000rwhp you would choose a compressor capable of supporting 120-150lb/min (higher wheel mass than necessary) to keep the operating adiabatic island near a comfortable center point while negating the additional wheel mass by using nitrous and spark strategy. However in a street application for 1000rwhp that will never see a race track or nitrous you would want a compressor which can only flow roughly 105 to 110lb/min to minimize wheel mass. The question of 'when will it spool' and 'which turbo is more efficient' is never considered in those efforts because mass throughput and application supersedes whimsical desire for a faster spooling turbo which may not exist (it won't be easy to tell without comparing each turbo in the exact application and situation since they are all so similar in the same mass-rate range)
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