The 545 is a beautiful car with speed and handling performance that is exceptional. However, the iDrive is very difficult to navigate and we had problems with error messages on our screen from the beginning. There was always at least one and sometimes as many as 3 warning displays. The dealer was never able to fix them and didn't respond to our continued complaints. We finally turned it in about 24 months into a 36 month lease.
The 545 is a very fast and great handling car. It looks sharp and overall it is very fun to drive.
Get rid of the iDrive and all of the fancy electronics. They are so convoluted and difficult to use that it is a chore to adjust even the AC when driving.