Like many guys looking to upgrade their bottom end, I was surprised to see how expensive the current solutions are out there (at least compared to what they offer). IMO both the JL and the Bassforms are ridiculously high priced. I went to a couple of local guys but wasn't impressed by what they offered either (and the price was not that much cheaper).

Finally, I took my search back to the net and I found something I wanted to share. The box cost cost me $150 shipped and it is built right and fits perfectly. You can order it in a bunch of different configs (i.e. 1 10"/2 10's 1 12"/2 12's, etc.) and even customize the demensions if you need to put a deeper sub in (magnet longer than 7"). Knowing how difficult it will be for the bass to be felt in the cabin, I went with 2 12's setup. We all know that bass is omni-directional, so I am not so much worrying about HEARING it as much as FEELING it.

This box (filled with a couple of Rockford Fosgate P2D412s)+ my 8" SWS Earthquake upgrade should give me what I am looking for. The link to the sub box vendor is http://cgi.ebay.com/BMW-2003-2009-5-Series-E60-Subwoofer-Box-Enclosure_W0QQitemZ380116359817QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item5880b35a89
Now for the pics...

 

this looks good, would have been better if they left little spaces on the sides to mount a couple amps...
curious to see where you will mount your amps. post up after install to tell us how it sounds...
doesnt look too deep which ive always had a problem with in the past (angled/narrow boxes)...

 

Cool box. Looking forward to your review.

 

I put my 2 amps in my spare wheel well...!!!

 

no rattling?

 

Yeah. that's what I'm planning to do. I'm thinking of building a wood platform.

 

any pics of this in your trunk? I wanna see how it fits.

 

Don't have any pics of that yet, but I did dry fit it and and looks just like it does on the ebay website. I can put it back in when I get a minute and take pics if those aren't good for you.

Let me know.

 

Let me upload some pics later today. The amps are fixed into the wheel well so theres no rattling/movement. The subs are also fixed in pretty tight in the boot so no rattling even with the bass all the way up!

 

See some pics of my subs and amps....

There is still plenty of room in the trunk to use for luggage etc....