I am selling he above amp which was fitted to my 330d for 2 months.
335d has HK fitted so I don't have any use for it, although the HK sounds awful compared to my old setup. I will be throwing in the Bluetooth USB dongle which plugs into the back of the amp and allows you to fully configure the output and frequency response to each channel (speaker)
With being a digital unit it is very small, so excellent for stealth installs and also doesn't suffer from heat management issues like standard amplifiers.
Cost £450 new - after £200. In box me for further details.