Just get a rear sway bar. For a car as light as a CRX or civic, you want the front end to be a bit looser than the rear. Install a rear sway bar, it'll almost entirely eliminate understeer.

As for brand, ST and Eibach are both really good brands, and both of them will install easily if you have a stock exhaust. If you've got an aftermarket exhaust, the ST one may require some moderate tweaking of the muffler and tip, depending on the setup. I don't know bout the Eibach.