It gets really cold driving a car without a heater in the winter. Unpleasantly cold. This observation coming from the rolling electrical malfunction that is my dsm, with no blower motor last winter. I would leave the heater stuff in.

Front and rear bumpers are heavy on TELs, probably the same on Galants. 30 something pounds each. There are a bunch of heatshields above the driveshaft, on the gas tank, etc on a TEL, a good 10-12 pounds to get rid of. Going to a stainless 2g clutch line let me get rid of the stock clutch line and bracket which on my car weighed 2 pounds. Spare tires are about 40 pounds, but you've probably already gotten rid of yours. Automatic seatbelts are about 30 pounds total with all the wiring and tracks and motors, I replaced mine with 5 pounds worth of Suzuki Esteem manual seatbelts. Then again the galant might already have manual seatbelts... I've never been in one. Stock wheels are heavy, my rx-7 wheels+ falken ziex tires were 13 pounds+ 22 pounds for a pretty good reduction over stock until I bent one of them. Still need to get that fixed by Transwheel but I'm sure you already have lightweight aftermarket rims. A sheetmetal intake drops 6-7 pounds over a stocker, and pulling the two support brackets for the stocker drops 4-5 pounds. I could keep going but a lot of what I've pulled from my car might not apply to the galant.