The examples being lets say BMW E46 M3 and the new BMW G80 M3. The E46 has a 3.2 i6 NA that makes 338hp, the G80 M3 has a 3.0 i6 twin turbo that makes 510hp.
What technological advancements have been made, other than the turbos and 20 years, that separate these 2 cars?
If you know something really technical feel free to share.
In generally the biggest advancement on ICE engines on last 20 yrs are materials (lower internal friction), better control of mixture forming and burnign (better control electronics, direct injection, etc)
Not all of these advancement are nessarily for good in terms of durability IMO.
But for you question, take std.M54B30 and slap couple of turbos to it and it gives easy 500hp. Rebuild it to suite and you have more with reliabilty, so you dont need modern engine to make power, those turboes does most of the work.