are you using a 4 channel amp?

Try disconnecting the dash tweeters, as you may be getting some cancelation... doing this will either prove or rule this out.

The stock door speakers did not have tweeters... possibly had "whizzer cones" for extra highs... these speakers had greater dispersion where the tweeters of the new bostons have more directed high frequencies. The fact that they're pointed right at your legs is not helping you.

Next, I suggest is moving your new bostons to the rear and get a component set for the front... you say you like brightness, so Infinity and MB Quart come to mind... their tweeters tend to be very bright. Its best to keep the tweeters fairly close to the mids, but I have had good results putting the new tweeters in the dash in Hondas.