Is it true that the touring/saloon uses a different sized unit to the coupe/convertible? I am looking at 2nd hand ones and want to make sure that I buy the right one!
I believe the changer is the same (excepting that there are changes in models over time) but the mounting brackets are different. If yours is an Alpine I think it should be a straight swap. Mine's an e39 5 series, & they're the same.
I fitted one to a W-Reg 318ci coupe I had before the convertible I have now and it was pretty straightforward, you just need to know how to unclip the boot trip, and be confident putting that all back.