I might consider 2 tweeters per side. I'd have to figure out how to mount them though. I'm trying to use my factory tweeter location (A pillars), and I definitely can't fit 2 tweeters or anything with more than like 70mm overall diameter and not a lot of depth either. Might consider some modification but that's not my thing and I don't have the tools. Looking at some sb acoustics tweeters and some other small-ish ones on madisound. I found a site that compares almost all the tweeters sold on madisound, still reading through it:
Zaph|Audio
He talks of enclosures and infinite baffle as if all the pro audio / madisound / parts express tweeters need an enclosure. Do I have to put them in an enclosure? Because I thought I could just mount them as normal in the factory location in the A pillars.