Sorry, can't help you with the distribution policies of BMW in the US

Here in the Great White North, the 550 with premium/nav is $86,600. The M Sport package on top of that is another $7,500 (9%) and gives you the following:

M Aerodynamic Package, M Multi-Function Leather Sport Steering Wheel, Sport Seats, Anthracite Roof Liner, M Sport Suspension, 19" M Double-Spoke Alloy Wheels - Style 172M, High-Gloss Shadow Line. (Deletes heated steering wheel)

The M5 is $115,500 with no options, which is 22% higher than the loaded 550, or 33% higher than the 550 without the M sport package. Given that the M sport includes more than just the cladding, it looks like BMW of Canada is conciously bridging the (large) gap between the M and non-M models in both price and equipment. Perhaps the same strategy will trickle down to BMWNA.

I agree that the new M3 is likely to go a fair way up the price ladder. It appears the filler model will be the 335, whether it is a turbo 3.0 litre (as rumoured for Europe) or a NA 3.5 litre (as rumoured for North America)

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue