Well, now we ended up with a question: why should the OP think about upgrading to another BMW, if his 550ix LCI seems to be the top (FWD) car? Actually why not
There are different rumors about the
next generation G30, while introduction of a 600hp M5 FWD is still not excluded. Its direct opponent Mercedes E63 AMG already has the FWD and this is IMO а very serious advantage.
Update from BMW M:
The new BMW M6 Coupé, new BMW M6 Convertible and new BMW M6 Gran Coupé.