Stainless Steel brake lines for all 4 corners
Upgrade brake shoes, pads, rotors
Bilstine upgrade shocks
Suspension coil springs wink wink... not the stock parts
Exterior Chrome package KIT
Wheel arch extensions (Fender flairs)
Air dams
Rear exhaust valences
Side skirts
Center arm rest kit
DLR module
Cruise Control module
Access to MB parts and maintenance manuals (I know near impossible but you asked)
Find a competent technician willing to use the MB computer to install an new "tune" re-flash (even considering warranty issues there will be a market for this service)
Smart Car swag like caps, t shirts, and dinky cars
MB tri star emblem
Basic front stock steel wheel and tire as spare
Selection of Perrili, Toyo, Kumono etc tires
Selection of 15", 16", and 17" rims in wider widths
If Smart says there is warranty or safety issues, I call BS. German TUV is much stricter then USA DoT ever thought of in this regard. Most German Smart dealers fit the 451s now with proper offset Brabus rims in 6.0Jx16 and 7.5j x17 with 195x55R15 through 205x45R17s all the time and they provide the proper TUV cert.
I agree fitting rims that require a spacer and 3 lug to 5 lug adapter will never fly from the dealer.
The stuff I am seeing are direct replacement wider rims designed for the 3x112.5 lug spacing and proper offset. There is not a wide selection in styles but they at least are better looking and wider then the factory 9 spoke we are getting