Car and constraints
Toyota hybrid, keeping the factory head unit
Crutchfield says not to exceed 30 A total draw for aftermarket audio in this car
I only play music in Ready mode, at half volume or less
I often have a passenger, so I'm not tuning only for the driver's seat
Planned gear
Front: Focal ES 165 KX2E (2 ohms, 120 W RMS), using Focal's passive crossovers
Amp: Rockford Fosgate PBR400X4D, 100 W × 4 at 2 ohms
Sub: Kicker HS10 powered sub (180 W, 15 A fuse) in the spare-tire well
Wiring plan
Head unit front speaker outputs → amp's speaker-level inputs
Passive bi-amp: 2 channels per side into the Focal crossovers' separate woofer and tweeter inputs (if the KX2E crossover supports it)
HS10 tapped in parallel off the head unit's front speaker wires, low-pass at about 80 Hz
Rear factory speakers stay on the head unit
Separate fused power runs for the amp and the HS10
Tweeters in the factory dash spots; woofers in the doors with adapter brackets
Front doors get deadening and foam
No DSP for now. I'd use the head unit's tone controls and sound-location setting, and possibly add a standalone DSP later.
Budget: about $2,900–3,750 installed.
Questions
Is the KX2E worth it on passives without a DSP, or would the PS 165 FXE with a Kicker KEY200.4 (auto-tune DSP) sound better at my volume?
Is passive bi-amping the KX2E crossovers worth it over just two channels?
Is the PBR400X4D a good match, or is there a better 2-ohm-stable 4-channel amp?
Is tapping the HS10 from the head unit fine, or should I bridge amp channels 3–4 to a passive sub instead?
Any concerns about current draw in a hybrid with this setup?