Box for 05 RE XXX

so i picked up an Fi/RE xxx 15" the other day. i had a 4.3 cubic feet box, tuned to around 45 hz, for an aq hdc3 15" sub. well, the RE XXX doesnt like it. it peaks very high, and needs to be in a new box, or i need help on how to re tune the box.

any help is appreciated, would be willing to get a new design.

max size is 32" wide, 17 tall, and 18 deep.

its in a celica hatch back,

and lastly, i peaked in my car at 49 and 51 hz in the box listed above. so a few hertz higher than tuning. specs for the sub are here.

Specs on the 2005 RE XXX 15 - Car Audio Classifieds in winsid i got around 3.5 cubic feet at 30ish herts. but id rather have someone do it that knows their ish.