I am at 6300 miles on my '21 GTR. I typically average around 20MPG as well on 93 octane gas. I had one long trip(~1000 miles) where I got close to 25MPG but that is by far the best I have seen. With primarily around town driving (and not "big city stop and go" either) I get around 20-21. Much less than my '19 GT which routinely got around 25-27MPG under identical conditions.