I will have a separate part out thread, but this is a pretty specific post. I sold my 650 but removed the M6 exhaust, bumper trim, and M Performance carbon fiber diffuser.
The exhaust has less than 5k miles on it. Cut about 16" back from the muffler (approx.). No dents, tips are near perfect (few scratches will happen). I also have the M6 bumper trim piece (painted carbon black but you can re-paint). Also, the BMW M Performance carbon fiber diffuser. All pieces are as new. I will include the receipt for the diffuser if you wish so you will have almost 2 years of BMW accessory warranty coverage.
This is all you need to convert your 650 (you must confirm on 640) to the quad tip exhaust setup. A good shop can do the install for you with no issues. I will send more detail pics if requested via PM. All parts are off car and I WILL SHIP at cost based on buyers location with my UPS discount.
If this doesn't sell as a package, I'll consider selling individual pieces. Thank you!