Ill get right to the point

JBL Sub is blown, and i'd like to replace just the sub w aftermarket if anyone knows one that is better and fits, its not a round basket, its like a PHL basket, dual voice coil..my wife will not let me add a box so everything i want to do has to look stock but id like to add a bigger amp and a better sub speaker in the same enclosure
next can i bypass the nav protection do dvd's can be watched on front screen (passenger)

looking for best and coolest way to add aux input to my system without having to switch anything, NO FM through cassette, want direct input

thanks in advance

trying to get this done for my wife's birthday on aug 9, randy