[Christ]

The CR-X Vtec (Si-R in Japan) has a B16 1.6 liter DOHC Vtec engine in it. Your engine wasn't designed AT ALL for economy, you basically got the race-version of the CR-X.

If you're considering modding that car, stop it :P It's invaluable. It's so rare to find that particular model (that I'm aware of, anyway). Sell that car for it's actual value and buy another CR-X, preferably the HF model.

Mugen makes/made a flush mount rear spoiler that is essentially a hatch-extension for your car.
If you want to permanently remove the rear wiper, remove the whole hatch and find one in the same color that doesn't have it. It's a lot easier than doing body work, you'll actually get money out of it, and you can change the weather seal while the hatch is off.

The antenna can be removed easily and replaced with a block off plate that costs about $2 US from Honda. It's a piece of plastic that screws in using the factory hardware, and comes with a new gasket.