I have just installed a JVC avx830 http://www.caraudiocentre.co.uk/search.asp?criteria=avx830 which has a detachable facia. Its has blue tooth, plays dvds and many more options. But the biggest difference is the quaility of the sound coming from the original bose speakers .
I installed this myself and I have never had any experience installing a HU before, quite scary at first but in the end afterwards I had a massive big grin on my face . There are quite a few DIY guides on the net and a member here (yokomo) was great help when I couldnt get any sound from my install !!