I just went to an Acura Dealer here in Plano Texas. I asked the same question and the sale person said that it would work with regular unleaded. I then went online and found out the TSX is just the European version of Honda Accord. On the European website they didn't even bother to put the 93 rating on the 2.4 liter engine that the TSX has. So I guess you will experience no less in performance.Good luck.