I was one of the ones that mentioned the fuel economy of the M3, I guess I should explain myself:
The primary reason this erks me a bit is that I tire a bit of reviews of expensive high end cars that are so great. Why? Well if they are expensive and high end, they really should be great! For those endowed with money, that is fine, but for the "common man" it is not realistic. Normally I would say GRM would get a pass on worrying about economics, because of the performance focus, but there is the "Grassroots" in the name.
This is primarily a complaint of other magazines / shows that review cars. (hey, the new $75,000 supermobile is great!, ya no sh#&t, it's 75 grand, it better be great) It just seems that a car review should be an overall review and they all seem to leave out the economics when weighting the measures. Its kind of like reviewing cars by driving them around a track. Well that is great if you buy it as a track car, but not terribly relevant for an everyday car. It reminds me of computer (Apple mostly) reviews I used to read and how they would complain so much about how hard it was to do upgrades to the computer. Well, as you may know, very few people ever upgrade a computer, so it was a bit silly.
From my perspective, if there is a "good" car (using the common review standards) that cost twice what an "OK" car does, the "OK" car should get as good or better rating. And, of course, these days, fuel economy hits very hard and has a big overall cost effect on cars.
What is my idea of a current 5 star car? Well, I don't deal with new cars much (my newest is 43 years old), but as an example, if a new Miata was $18,000, from a GRM perspective, that would be a 5 star car. It might not be for the average driver, but for a GRM reader, that is tops. Because Miatas push $25 grand these days, I am not sure they rate 5 stars. Also the fact that the Miata really doesn't get the mileage that you might think it should might hurt it a bit. (for a car that light, it really should do better, but I do understand it is more performance optimized than other cars).
The MINI's and the MazdaSpeed 3 might also be in consideration. Both combine amazing performance for the money and the mileage. Should the new Skyline be a 5 star? (it might be faster than the M3), well personally, I think it wanders so far from "grassroots" both in price and execution that I wouldn't think so (even if it is a great overall ride)
A real new 5 star car? Re-issue the 87 CRXsi, that's would be an easy 5 star, even if it is wrong wheel drive. (and yes, I know it will never happen)
Just my opinion.