This is an awesome setup that I had in my bmw 08' 135i for just a few months. The fiberglass box was professionally painted black saphire metallic. It was installed and fabricated by Rolling Thunder in San-Rafael, they are known for their award winning car audio department. I still have the receipt. The custom box gives the ability to still have trunk space instead of filling up your trunk with heavy wood boxes. It looks incredibly slick and very sharp, almost looks OEM it's so seamless. I would imagine it would still look great on a non-BSM 135, and there's always the option to have it painted again at a body shop. Here is the lowdown for what I paid:
12" MOREL ULTIMO 12 CARBON FIBRE SUBWOOFER- $899.95
CUSTOM FIBERGLASS SUB BOX BUILT TO FIT IN A 135i- $1500
SUB BOX PRIMER / PAINT- $250
SUB BOX PAINT PREP- $50
The sub weighs 15.8 lbs and the box weighs 16.9 lbs for a total of 32.7 lbs. Not bad for the high quality low end it delivers.
This very high quality sub and box cost me a total of $2699 before installation and was only used for about two months, it just got broken in really. Letting it go for less than half-price, shipping included anywhere in the continental US. I put this system in when I had about 2k miles and I sold my car last year when it had 4.5k miles just to give an idea of how little use it has had. I sold my 135 since I am trying to buy a house and needed less debt on my credit or else I would have kept this awesome setup.
Feel free to check my ebay profile, Neeko415, to see my positive feedback ratings. I pack very well and ship fast with tracking numbers. My number one priority is to make sure the people I do transactions with are 100% satisfied.
Let me know if you have any questions, thanks 415 279 2697 Nick
lostinbass@me.com