Help building box for 2 12" sundown x's

[Joe X]

Good luck. It's not safe to give you a box design for those subs. I sure as shit wouldn't want to be blamed for a failure of the subs because you decided twice the RMS a good idea. Wire at 2 ohms or get some subs that will handle the power, like AA Mayhems.

I guess ill be getting a smaller amp now....how does a 3500 crescendo sound its still more than what there rated at but its less power

You can have your 5500, you just can't push all the power to the subs, limiting your gains would be enough if you know how to do it, it's never bad to have extra fire power, the next upgrade might need it.