I've also driven my brother-in-law's '99 2.3 and noticed that it is much quicker than my 2000 at highway speeds. To further illuminate my situation, the comparison I've been running simple. Basically, I stomp on the gas at around 70-80mph and see what happens. while my car does accelerate, its not impressive at all. I'm wondering now if maybe that whining I hear at highway speeds with the top up is the rear differential.