I just removed all the tar that is under the carpet on my crx. Took about 15 to 20 pounds of dry ice, a rubber hammer,a chisel and about 3 hours. Came up relatively easy considering my car has sat in the sun with no carpet for the last year or so. I have all the shit in a bag and it feels to be more than 20 pounds or so. If you wanted you could put all your carpet back for a stock look.

Remove all the a/c and heater stuff and save over 30 pounds.

Cut out the skeleton of the stock hood for a solid five pounds. Make sure to leave the part for propping your hood up. Same thing for the trunk.

There is another 30 or so pounds of tar on the bottom of the car. Oven cleaner and alot of work is required, also a lift.

That is all the ingognito stuff I can think of right now.

50 pounds saved is a VERY noticeable difference. Think about it if you could get 100 pounds out that is about 1/20 of your cars total weight as of now. Definitely good.