My suggestion is to always go and listen to the speakers at a car audio a shop (not an electronics mega-store), the sales crew are more knowledgable for the most part. Listen to the same 10-15 seconds of a song, try a different speaker (same 10-15 seconds) until you come up with one pair that sticks out. Dont you or let them adjust any bass/treble settings, you want it in the middle to get a fair comparison. Make sure you find the exact set/brand you want, because you'll have them for a while. I have run my Infinity Kappa's for about 4 years now and been extremely happy with them. At my old shop, I had a choice of 50 different brands I could choose from (we only carried 5-10 brands but others could be had

) . I chose the Infinity's because of their clarity and frequency range, and the tweeters are a silk-dome which are more subtle, more pleasing to the ears than a titanium (which is what a lot of companies have). Good luck shopping and listening. Hope that helps...
Bill
btw, in your sig you didnt say anything about your 1980 chevy longbed...