2004 Ford Explorer stereo system

If you were going to run 6x8 4 way speakers, would you add tweeters, or leave the highs to the 4 way 6x8's?
Also, would you more likely run midrange woofers, or a midrange, and a subwoofer? Or even 2 mids and 2 Subs?

I'm not looking for competition bass, I'm looking for a really good, all around, car stereo I want to hear everything the music has to offer and maybe have some decent bass in the process.

Why does it matter?

It all depends on what you want, what kind of money you have, how much you're willing to spend, etc.

There are people running a 5000 watt system, a 10,000 watt system, a 20,000 watt system, etc. Why? Because they have the money and that's what they want.

I wouldn't run a 4-way 6x8" speaker in the first place. There's no point to having four drivers on a speaker that size, so it's most likely aimed at uneducated buyers who assume that a "4-way" speaker must be better than 3-way or 2-way. But if you are using a 4-way speaker, adding even more tweeters would be a bad move.

My recommendation would be a high-quality set of 6-1/2" component speakers installed with an adapter plate to make them fit the 6x8" speaker locations in the front. Then add a single 10" or 12" subwoofer to take care of your lows. You can use a 4-channel amp with two channels driving the front speakers, and the other two bridged for the sub. If you need rear door speakers, for rear seat passengers or because you like to have some rear fill, use a decent 6x8" or 6-1/2" 2-way that can be driven by the head unit.

In car audio, less is more. If you keep adding speakers, you'll end up paying more for poorer sound quality.

I would not use "4 way" speakers.
Too gimmicky and usually not as good as simpler ones.

A 2 way setup of separate woofers and tweeters should be good enough for most people.

If you wanted more bass, you could add a sub.