sometimes b stock amps will have more problems that wont be noticed until the amp is blown...again. its a roll of the dice. if they still comewith a warranty i wouldnt see a problem in buying one.
concerned about the rearmost midbass in that door: will the door close? it looks lower than the bottom of the panel. and do you have your tweeter placement figured out yet?
cut out holes on the trim panel and hide it with the carpet that way the heat can still escape but it looks like a solid piece. btw great job, not many people understand the importance of making trim pieces that meet the factory panels.
you should be louder. more cone area, same power, and you dont have to put it in a trunk. im also pretty sure your front stage will beat the blahhpunks.
turn that lowpass filter off on the mids. cut em around 25-3k and let the tweet take over. you may want to try a different slope too. i recommend 12db slope.
your subs should be at 50-63 and lower, 24db slope is fine for the subs.