I find that you can get a lot of bang for the buck with most pioneer speakers, and at least back in the day they mated very well with their own head units, though I would have expected brand-matching not to be a thing. Problem is, the focus probably has a pillar tweets, so adding a pioneer with tweets to existing pillar tweets is a lot of tweets. So really, if you do have factory tweets in the pillars, you’d need to disconnect those or disable (preferably via low-pass filter) the new 6x8s.
or put in full separates, with the xover mounted where it would serve both door units and pillar units. The problem is, so many of the component separates Ive used are seriously harsh with 3-6 dB needing to be dropped out of the tweeters. Ive had to build compensating networks to get it right, and some HUs now provide a decent approximation to do the same by guessing the x-over frequency and then shelving down everything above that. If this is sounding complicated, yes.
with Ford factory, one of the best things I’ve found is to stick the oem woofer back in, and pull the pillars off, and cut the extra plastic guard (cage) off the front of the dome of the tweeter. it’s a small diffference, but it’s a nice difference.
beyond that, however, Cujet nailed it up above, nailed it to the wall. the oems get a surprisingly good sound out of cheaper components because they optimize the design to work well, with the math up front, allowing them to use cheaper components designed (tuned) to work well together. We can buy “better” stuff, but we then have to go through a ton of re-optimization (tuning) to get it to all line up.