I have 2 sets of MB Quart QSD 5 1/4" installed in my Xterra. I have blown 1 mid on each set. I would like to buy 6 1/2" mids and put them in the front and have the MB Quart 5 " set in the rear doors. I would like to spend 300ish for the mids, maybe Morel or? The amp for components is a Diamond D7 6 channel that biamps the front set and uses channels 5 and 6 for the rear components. A JL10w7 and a 500/1 in the carge area. What are your reccomondations for new midranges and is it a bad idea to switch from MB Quart. Thanks