Picked up a BNIB Fi BTL N215 Fully Loaded yesterday.

I'm looking for box suggestions.

I'm looking to get the most out of it with the power that I have.
Right now I have a Sundown 1500 for power, C&D 75ah in the back and 1 under the hood, H.O. alt

My initial thoughts are like 5ft^3 tuned to 33-34hz --daily box.
Or should I just build an SPL box for competitions----any suggestions on size?

Sexy Mofo here!!