What are the best 6×9 speakers to put an amplifier on?

There are plenty of good 6x9 speakers, but I always recommend these. a href="http://www.techronics.com/caraudio_9935_Polk-Audio-db691-6-inch-x-9-inch-3-way-Car-Speakers.html" rel="nofollow"http://www.techronics.com/caraudio_9935_…/a