500 watts would give you a healthy amount of output. Plus it wouldn't drive that sub into distortion levels. The problem is, if I remember right, the Plus 2 is a dual driver sub, well what kind of impedance load does that present? If it is like 2 ohms, that might be kind of tough on the Bash amp.
If I were you I might look at an outboard amplifier like a Behringer iNuke. Maybe even a two channel amp that can power both woofers separately. I would make a wood board cut out that fits the plate amp hole, put a speaker wire terminal cup in it (or two for both drivers and amp channels), and use an outboard amp on that.