Yeah I agree it's sorta all or nothing these days.
4-cylinder engines are stretched to the max and really can't extend beyond the 2.3-2.5L range which limits them to 160-170-ish hp, unless they're made into 7000+ rpm top-end beasts (Acura TSX). But you end up trading off a lot of efficiency in order to make a 4-banger perform like that. A TSX auto runs low-16's with 205hp/164tq, but does not manage better fuel economy (22/31) than a 269hp Camry!
The other strategy is to use turbocharging, but when you're cruising and off boost, turbo engines still have much poorer thermal efficiency than a naturally aspirated one and still don't get the mileage. I've seen lots of claims to the contrary and a lot of big talk about how variable turbos and direct injection and yadda yadda will fix everything, but the end results never add up. A new Passat with the 2.0T engine (direct injection & turbocharging) has 200hp/207tq, but also gets 22/31 mpg with the automatic.
For 22/31 mpg, would you rather have 205hp/164tq, 200hp/207tq, or 269hp/248tq. That one is a no brainer.
These new GR engines offer unbeatable combinations of power and efficiency. I don't really "need" that much power either. I'd like to see a 3GR-FSE 3.0L engine in the Camry from the GS300. That would give more than enough performance, and could probably nudge the fuel economy to 23-24 mpg city, and 32-33 mpg hwy. All other factors being equal, smaller engines are still more efficient. Less friction, more efficient combustion, and internal combustion engines operate more efficiently with heavier loads on them. Using larger engines but having them more lightly loaded much of the time works against efficiency, not in favor of it.
