As all say, do it right, If you don't, you'll eventually want to tear it all apart again because you'll wonder why you spent money on speakers that don't REALLY do their job.
As far as speakers go, I really like what memphis audio has been doing, I run them in my jeep tj and the quality is amazing, not to mention the sound of these things, I have them running off of a 4 channel rockford fosgate amplifier, but I did run them off of the head unit for a couple months while I waited to get off of work and for the weather to warm up. top down, doors off, still clear as anything. just amazing speakers and more than worthy to go into the sti.