Ok, in order:

I'd consider changing the subs, the L5 isn't really much of a SQ woofer, especially ported, and even more so in a wagon as you'll hear any port/cone noise easily.

If the Soundstreams are Exact's I'd keep them, if not... consider replacing.

Tweeters in the A pillars are usually used to only play very high frequencies to raise the sound stage. You would either need to build a passive crossover for them or add an amp.

I'm anti center channel unless you're doing 5.1. Same with rear fill.

PLD is important... but out of the doors you will never get the PLD's close to equal. People use kickpanels to get the speakers further away and get them closer to equal. You'll be limited coming out of the doors.

If you add a midbass to your 3 way you could use your passives on the 5.25 and tweeter and your 24xs between them... if you can get the right frequency chips for the 24xs. Or, you might choose amps with internal crossovers. Another option is an external processor that could cross everything over, and provide equalisation, and give you your center channel even...

Aiming the midbass speaker is not very important as bass is not very directional.

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