I am going to be helping an M5 owner with replacing his dash. besides the obvious, are there any particular tricks or "good to knows" in doing this job? I'm an e24 guy, so I know we should remove the center console and cluster, I figure it will be pretty obvious form there, but just in case. And is it easy at this point to R&R the heater core? Does the A/C unit need to come out to make it easy like in the e24? Thanks for your help! Mark