Doesn't look like you are getting even close to stressing the subs power wise those should take 400rms each.
If you are running them in a sealed box at the recommended volume, the power you gave to them should not have damaged them.
an unknown tune ported box is a different story.
any of your buddys have anything half decent amp wise that they can lend you to check the rest of youre set up out?
Something that will definately put out 500rms or so at 2Ohm, mono or 2 ch bridged, start from there