Acceleration = force/mass
so anything we can do to get the weight down a bit will help. In the owners handbook a 1991 944 turbo weighs 1400kg

The following can be removed:

Spare wheel, Jack, Toolkit, Compressor
Rear Carpet
Rear Seat

1) Remove the rear seat back upper part. Use 10 mm socket to remove the pivot bolts.
2) Remove the clips at the back of the seat bottom (may be underneath the luggage compartment cover)
3) Remove the seat belts.
4) Use your fingers to loosen the grip between glue holding the seat bottom and the chassis. There is additional glue holding the lower carpet to the seat bottom front.

Stereo, Door speakers
Catalytic converter

The front seats are heavy at over 25kg each. The 968 Club Sport seats will fit but these are expensive and still heavy at 12Kg. Racing seats can be found (e.g. COBRA Imola GT) which look very similar but weigh less than 6kg, a saving of 38Kg

Wheel Weights:

I used a fairly accurate bathroom scale for the following weights.
They may be off but they were all double checked and off the same scale.
Here's a sampling of wheel weights, in lbs:

The aftermarket wheels weigh 6-10 lbs more than similar factory wheels.
That is A LOT!

I was also surprised at how light the HRE wheels are even with cast centers.

Phone dials are also much lighter than I expected.