I'm creating my first HT and i need a sub.

What i've got is kinda a mix of stuff i've picked up over the last few years because i'm on a budget but i want something that will last me forever.

Dennon AVR-1705 with 2x Athena AS-B2.2 as fronts, Klipsch RC-62 center, then cheaper Klipsch surrounds and a custom-designed 3-way rear on a seperate amp - assembled in the klipsch lab (science-fair project actually)

Anyway, it's all in a basement(16x23x10) that has concrete walls all around but a good amount of acoustic treatment on the walls.

Is one LFM-2 going to be enough to give me enough low-end to measure up? or should i get two? or maybe one and a buttkicker?
Any and all feedback is greatly appreciated! Thanks!