It was just a rough comparison, I know the whp will vary 20-30% depending on the dyno.

The way I pictured it going would be that you would have, on one extreme, your average Honda making ~140whp and getting 30mpg pulling around a 4, and on the other extreme, a Ferrari of sorts making 400whp with 10mpg, overall ratio around 40.

Your factors of varying drivetrains will show up in the mpg results since AWD gets worse mileage than FWD or RWD. Similarly the weight is built in because mpg is a function of weight.

I'd think this comparison will really favor turbo cars because I know a few people running ~360whp and still pulling 18-20mpg. He'd pull an 18, which I would consider even more efficient since he's pulling more power and using about the same amount on a daily basis.

Anything less than 10 is probably going to be something like a hybrid or POS honda thats so slow its not worth driving.