Please do compare any subwoofer under $500 to any subwoofer in the 1K range. Yes there are subwoofers in the $500 range that are good woofers for the money (Hsu). Yes there are subwoofers in the 1K range that suck. Cross-reference the two and see which group sounds better on the whole.
The ML Grotto would be around $600 if factory direct. Guess what it is not though... factory direct. Factory direct products can save a consumer money up front. However, if there is ever a problem with the product shipping (especialy on heavy subwoofers) can eat away at these savings. Also the advice on products from reputable dealers can save a consumer money by getting recomendations that better match the individual system than the compilation of glowing reviews for products that may or may not be all that they are cracked up to be. Try to get advice from Tweeter. By the time the well dressed salesman finds the appropriate pamphlet the average consumers attention, interest, and confidence in the store has wained.
The bottom line is that you can expect BMW performance out of a Honda but all of the magic pixie dust and snake oil available in the audio world (and there are lots of both available- would anyone like to purchase a jar of magic rocks or an $800 interconnect for your $900 subwoofer?)will not make it so.
My two cents.
