The RMP101 fits up to the 2007 year model Ranger, that I know of. Are you sure the cab of your 2011 is the same ? I know they look the same but they can still be different as to how the enclosure fits. This one that fits your Ranger
http://www.crutchfield.com/p_236RM10...al.html?tp=129 is .6 cu. ft. sealed with a 5" mounting depth. That sub
http://www.crutchfield.com/p_13610W3...and%7cJL+Audio has a mounting depth of 5 7/8", so it won't work. Also, the amp outputs only 300 watts RMS to a 2 ohm load, and that sub wants 500 watts RMS. The C2's are rated at 60 watts RMS each and the amp outputs 75 watts RMS to 4 ohm speakers, but you can tame it by measuring the AC voltage outputs with a DMM.
If you are set on using that amp, (not sure why you want to use all JL components) I recommend you find a subwoofer that fits and is made to use the space and volume, and is rated for closer to 300 watts RMS, and component speakers that will handle 75 watts RMS.
Also, with more than 50 watts RMS in your doors, you need to invest in some sound/vibration damping material for the door panels and some foam speaker baffles (beneficial no matter the power).