[ezmaass]

They're two very different cars, I'd say. You should just decide what you value most and see which comes closest to providing you with those values.

The M4 is smaller and lighter, designed to be tossed around a lot more. The M6 is a large GT sports coupe. The M4 will be more nimble, designed to carve corners. The M6 is designed to make it across a continent in comfort and luxury while at speed.

Without a doubt, the M6 is more luxurious - finer level of materials, much more leather surfaces, a few more gadgets to option, etc. It's also more powerful. But that all comes at a price, clearly. But as I said above, the M4 is clearly designed to be more nimble and athletic in the corners. It's not as heavy, and it's significantly smaller, making it more capable as, let's say, a track toy.

When you start to make one car a Swiss army knife, it becomes a large compromise - "jack of all trades, master of none." Know what you want to do with it - what matters most - and go after the car that best fits those needs. IMHO, the 6-series is best as a luxurious, sporty DD - something that gets you from A to B in a lot of style, luxury, and speed. But it's not a corner carver or track weapon. Get a different car for that purpose.