I am the proud new owner of a non-sport package E91. I would like to know what sort of seats from other BMW models I could possibly swap right into my new car. (Must be a clean, simple swap, no fabrication.) For example, would the sport seats from a 328i or 335 go right in, or is there any difference in the mounting rails? Are airbag hook ups interchangeable between my E91 and say, an E46 M3? Has anyone ever swapped their seats in situation like this? I'm not looking to spend a bunch of money -- but if a wrecked or parted out BMW came up available I'd like to know what would work or what wouldn't.