There's plenty of places to save weight on these motors, it just depends how far you want to go with it and what you intend to use the car for.
Seats, the standard seats are extremely heavy but you may need to adapt/modify brackets to fit lighter ones.
Air con, quite a simple mod to remove the system but be aware that in heavy rain, poor weather etc, the standard heater is very poor at demisting and you will be better off fitting wipers on the inside too
.
The rear steering rack and four wheel steer mechanism. The rear steer is controlled via a pump on top of the rear diff, when removing the rear rack you will need to retro fit the link arms from the MR version, a bracket needs to be welded to the rear subframe to locate these.
Carbon bonnets, doors, tailgates etc are available, mostly at a premium though and the carbon bonnet will need extra security via pins as it will lift otherwise and you'll see it in the rear view mirror.
If you intend to race the car there are many other options too.
If all you are after is a light car, you have bought the wrong one.
If you have a very wealthy bank account and can justify the extortionate prices Pit Road-M charge for their absolutely appaling fitment carbon parts, there are plenty available.