As per David's response, he helped me greatly when I was purchasing an amp and some speakers last year. The man knows his stuff.
This is a procedure to tune the JL amp
Whether or not you have a 2 or 4 ohm sub, it should say on the sticker, if not you can find out with an ohm meter. My guess would be that it is a 4 ohm sub as there is only one, but you never know. If 4 ohm, two of the amp channels should be bridged to double the wattage going to the amp.