C350: Mercedes ULTRA Custom Audio Build Leave a Comment / Audio, Custom Fabrication / By Ultra Auto Sound The factory Harman Kardon sound system is just not good enough for our client. Two JL audio 12TW3 subwoofers. A unique build. Wrapped in a leatherette. Two JL Audio XD300/1 amplifiers used to keep it a symmetrical design. Custom lighting Share This:FacebookTwitterEmailLike this:Like Loading... Related