Best replacement speakers for Deafcon III

[luckee37]

I'm looking to replace the Polk Momo MMC650 with external crossovers in my Deafcon III cans. I replaced all of the other speakers in the boat with MM651's and am very happy with the sound, but the 651s are too wide (and deep?) to fit in the existing cans.

I'd rather not go through the hassle of installing new cans and such. I'm wondering if anyone has found a good speaker that can slip into the existing mount without too much hassle.

Thanks!