Couple things, do a Google search of the model numbers, see what they are selling for on crutchfield, amazon, ect to make sure you got a good deal. Second, those appear to be very solid products, good buy in my opinion, especially for the right price. Dvc subs give you some flexibility with the ohms, for the amp you selected, you'll be fine either way. Jbl makes solid products. With that being said, as long as you didn't overpay,
stop sweating, you did fine..