@Davidwarren
For starters you should know that my car was a bog-spec European-delivery model with no sunroof and no leather/navi/logic 7, and a quoted curb weight of 1485kg (3271lbs)
Here is what I can recall from memory, along with a few weight deltas included for good measure. Note that I ended up with a 55/45 weight distribution FWIW
17x8.5 +40 Volk TE37SLs, 14.6lbs/ea, with 245/40/17 RE71Rs, also a relatively lightweight tire for its size
(-46lbs compared to stock 18s + RFTs)
Ti wheel studs (-1lb)
Dry carbon trunk (-9lbs)
Carbon hood (-22lbs)
Recaro Pole Positions, solidly mounted with lightweight brackets (-70lbs)
Rear seat delete (-53lbs)
Rear seatbelt delete
Rear Counterweight delete (-22lbs)
Pass airbag delete (-6lbs)
Armrest delete (-6lbs)
BMS Cowl Delete (-9lbs)
Magnaflow midpipes + catback (-20lbs)
15lb LWFW
23lb OEM 35Ah MB Starter battery
//M aluminum Rear arms are marginally lighter than stock as well, as are aftermarket coilovers.
There is a fair bit of weight to be shaved in the brake system should I choose to go there, without necessarily compromising performance, and I have a carbon driveshaft planned for another -11lbs or thereabouts...