I took out the jack, spare and tools, then replaced it with a can of Insta-flate tire sealer/inflater. A towing clause in my insurance takes care of the back up plan.
I also removed
rear seats
rear seatbelts
plastic body work and rugs inside the rear hatch
heat shields in the center tunnel and near the muffler (also aids aerodynamics)
smaller battery
lighter wheels from an Eagle Talon
rear wiper arm and motor during summer
engine balance shafts- also reduces parasitic losses and raises oil pressure, so lighter weight oil can be used.
There might be some other little things I'm forgetting.
Then I added about 15 pounds with a front mount intercooler and 2.5" piping.
It more than pulls it's own weight