You use aftermarket speakers, but don't like aftermarket head units? Ok...
why do you like aftermarket speakers?... Wait, I'll answer for you, because they SOUND better!
well, let me help you out there... Aftermarket head units do the same (produce better sound)!!!
you went through half the trouble of doing the RIGHT job, but you're trying to use stock tweeters? That and the half of the work you didn't do leads to lousy noise. You're speakers may KICK as you say, but unmatched tweeters/speakers and lack of propper crossovers, etc. just makes for noise!
do yourself a favor, get a set of separates for the front, with the tweeters and crossovers all set up. Usually, those sets will handle higher wattage as well.
Thank me later! Lol