Clean Slate Stereo System - 3K Budget

Putting a system in my buddies 2016 Craz and need to get components on order. 3K budget. He likes my setup in my RZR with 4X Rev 10s (Arc KS600.2), 6X XS-650's (Wetsounds HT6), and XXXV2 sub (Arc xdi1100.1).

He currently has a Fusion MS-RA205 HU and 4X Kicker KM61's. Wants to add only 1 pair of Rev 10's, another set of in-boats, and an insane sub.

I was thinking to stay on budget order a pair of HT4's for the Rev 10''s/In-boats since they are on clearance. Then still open to ideas for the sub and amp.

I was going to do zone control with RCA level controllers to keep it simple. If there is anything new that I missed in the last few years I'm open to suggestions as well.

Thanks,
Mike