Advices using Crown MacroTech 24 x 6 for sub

Hello everybody,

I saw a posting for a Crown MacroTech 24 x 6 in my area at a good price and I am contemplating the idea of using it to power my 400w 8 ohm sub.

Amp specs

According to the specs, 520 w at 1 kHz falls a bit short of the 1.5x wattage of my driver (which will be used lower than 1kHz), so I was wondering how much of a big deal it would be to use it anyway? Any recommendation/advices are appreciated. Also, an option I could consider is to replace my driver with a 4 ohm driver. However, I'm also thinking of eventually adding another sub to my setup, which makes me think I should go for a more powerful amp in this case.