Alyx is so full of stuff. Not even my BMW gets that kind of gas mileage. And if you put a performance engine in it, it's even less likely. Unless you're running on turbo diesel.
I drive a BMW with a racing engine in it and I get like 29mpg. Mind you, full carbon fibre body cept the roof panel and side skirts. Car weighs about a 1/3rd less than it did when I bought it.