[DoubleCrown]

Very little space behind the seats, I put a 12 in rear foot well untill I finish the trans hump/rear middle seat enclosure

 

[DoubleCrown]

Just some further consideration for the Hilux:
Alternator kinda sucks
You need to deaden the entire cabin, especially the fire wall. This means dash out.
Will need to drill the firewall to fit 0awg and grommet/waterproof fitting
Doors need alot of work to properly deadern and seal, the ute has basically none from factory. Will still have buzz from the window mech nonmater what
Will need to make your own solid mounts for doors, the pre-made ones are crap.
Air bags make pillar mounted mids tweets difficult.

 

[DoubleCrown]

You need to keep the vents unobstructed, it is allows the air pressure to equalise when you slam the door

 

[DoubleCrown]

I think your next step may be considering a DSP, but I like your set up. Jellous of the frogs lol. Are the tweeters pods the ones on eBay from Germany?