I hope someone can give me a difintive answer to this question. I have a 2001 M3 with Business cassette head unit and CD changer. I plan to add an ICE Link to use my Ipod and ideally at the same time I would like to replace the cassette head with a Business CD head unit so I can still play CD's. As the CD unit was available as an option, I assume this would be a simple plug and play but in checking the price of the CD player with the dealer, he said it would cost up to $2000 to install the new head unit. He didn't seem know what this would entail but I can't believe it could be that complicated. I see used players on eBay that seem to indicate they are easy to install. Does anyone know what is required to replace a cassette deck with the CD player?