I would estimate somewhere around 6k+ depending on condition. You'd really need to provide some photos to get a better idea. It's a 4 door auto 320i which are usually not high up in terms of desireability. Red isn't the most desireable paint code either but there will be someone out there who loves it. Is the interior cloth? Are they sport seats? Are there cracks on the dash? Full service history? Are all the electronics functioning correctly, these are the things that will make it worth more than 6k.