Wow...this thread is just saturated with ignorance:crap:
#1 transient response is not an issue with subwoofers, it is an inaudible phenomenon. Please do not recommend subwoofers because they are "faster" or slower"
#2 Have the dumbasses that blew their IDMaxes ever realized that thermal power handling isnt the only parameter to consider? There is a MECHANICAL power handling also, you can't expect to toss an efficient woofer in a large sealed/ported box with tons of power and NOT hit its mechanical power handling...jeeze. Power handling lowers (mechanical not thermal) when it is placed in a larger box with less air pressure. Thus the same excursion is achieved with less power...if you keep throwing more power at it its going to exceed xmax.
#3 The SQ phenomenon you are all raving about has to do with the FREQUENCY RESPONSE. Most subs have different frequency responses and are completely dependent on the install and transfer function of the vehicle. Have you ever considered equalization? Get the response of your car measured with an RTA, and boost the frequencies that are lacking and cut the frequencies that are exaggerated.
FYI prosound setups (ie those at concerts) are exorbitantly efficient. Correct me if I am wrong, but I believe you mentioned that you were craving a response similar to concerts. You can only have 2 of the 3 (small box, efficiency, low-end extension). Prosound rigs choose efficiency and small boxes for convenience and output reasons and as a result they have almost NO output below 50hz. An exaggerated 50-100hz is classic of concerts.
If you want to achieve this, toss it in a sealed box (bigger is better for efficiency reasons, but you most lower LF content with a HPF or limit power if you go that route) and boost the 50-100hz region and cut the