Yes, by law the any vehicle CAN NOT exceed the speed rating of its tires! The reason that the spec-v doesn't have any kind of restriction is the fact that it comes with Z-rated tires from the factory (149 MPH+). As far as the little bit of power difference between the two (or at least the proclaimed power difference), it is just merely tuning of the ECU (spark advance, air fuel ratio, etc.). I personally have almost always ran 87 octane in my '02 Spec-V because I could not ever notice a real difference except for a little bit of throttle response because of a slight advance in ignition timing. I drive too damn much to put 93 in my car and fuel is too expensive these days. If the motor had a turbo or high compression (12:1 or some****) then it would really need the higher octane, but with 9:1 (or whatever the compression is in the 2.5L) and fairly low horsepower, and not to mention an over sensetive spark knock sensor, you are just wasting dough pumping 93 into it. Oh, and as far as non Spec-Vs racing the Spec-Vs and winnig, it is very possible, especially if they are lighter and it's not a quarter mile (0 to 70 or some****) the gear ratios of the 5 speed might be at an advantage (you might be able to hit 60 MPH in 2nd w/ the 5 spd, I'm not sure, but use of imagination). Just my 3 cents.