Due to my broken radio buttons, I've just spent 2 hours taking my dashboard apart to remove the speedo and head unit/CD player. While it's all on the kitchen table, and before I send the button/|display unit away for repair, I wonder if it would be straightforward to do a satnav/touchscreen upgrade to the speedo unit. I can see R56 Satnav displays for sale on ebay and I guess I would also need a new Visual Boost head unit? Has anyone tried this or seen it done? I have the HK stereo upgrade and the head units with satnav seem to by Alpine - would that give me a better sound too?