IMHO, even the 4.8i will not give you the bang (its what i call it, the neck breaking acceleration) that is comparable to the M5. With 5 passangers merging onto a busy highway can get revvy very quickly with the 4.8i but really everyday driving 3.0 is just right.

I agree that it is subjective. Test drives don't do justice unless done a lot.

I trust that the 4.8 has enough power ( driving the 3.0 I thought i'd consider what if...) since it is the top of the line. just my 2 cents.

4.8 is fun but I would like more torque. Totally individually subjective.

p.s. Got my eye on that twin turbo engine on the X6...