If they really did feed that car regular gas, as it says in the review, then their performance and fuel mileage judgments are suspect. The Civic Si requires premium.
I had a 9th generation Si for a few years. It was great fun to drive, and the manual was one of the best I've ever had.
I don't quite understand Honda's styling choices for the Civic, though. The last generation was over the top with angled body lines and blank grilles. This current generation ditches all of that and looks like an Audi. In general I find Honda's styling schizophrenic; sometimes they hit one out of the park, and other times their designs are as dowdy as an old tractor, and there's no consistency.