It is a tight fit but not too bad, make sure you get your terminal orientation right. You want the positive towards the engine.

I did mine years ago, and it's been great, but I have plans to tear it all out and upgrade various items because I can't leave good enough alone.

Existing:
Dirty Parts Tray
Blue Sea ACR
Blue Sea Fuse Blocks (engine bay and interior sub panel)
Blue Sea Low Voltage Disconnect
Cut and crimped cables to length
Genasun MPPT Solar Charge Controller
Bunch of Anderson Quick Disconnects
Bunch of other add-on and accessories





I did a write up on the ACR here:
Blue Sea ACR - Automatic Charging Relays

I originally bought the 7610 but later changed to 7611.

Upgrade:
Relocate battery and upgrade to a compact lithium setup.
Delete traditional fuse block for Switch Pro 9100
Delete ACR for a DC-DC charger - Victron Energy
Delete Genasun MPPT for Victron MPPT for monitoring and reporting capability.

If all that provides me with enough room where the old battery went, I will install 100% duty cycle compressor from Hummer central air system.