I’ve been a victim of Conduit myself before. After going through hell to remove the settings it left in my Firefox profile, I eventually decided to install an addon to help protect myself from this bs in the first place: BrowserProtect. This prevents malicous addons from hijacking the homepage, search engine, etc. If something, e.g. you search engine, is changed, it will warn you, and let you keep or block said change.
Anyway, IMHO these toolbars should be illegal, assuming they are not already. At the very least, they should be opt-in instead of opt-out.