Alpine KCA-420i iPod Interface - Engadget - www.engadget.com Alpine is releasing the $100 KCA-420i iPod Interface for car stereos. Like the new BMW stereos, the Alpine system allows you to connect your iPod to your car stereo at line level and control it from the stereo head unit. This is great news, as the Alpine systems can be installed in virtually any vehicle, and the head units start at $200. There are some interface and usability issues (playlists are called files and song are called folders), but the sound quality is reported as being excellent.