I know this will be considered unusual advice to most people: you don't need to listen to them before purchase; nor will this be of any advantage. They are simply neutral devices; the only coloration of significance being the cabinet resonance, which is an issue on most speakers of all price ranges. You need to employ a high quality DSP management system with precision adjustments so that you can take advantage of this neutral speaker and finely adjust it's response to your ideal preference. This means you should use outboard amplifiers so that you insert the management system between pre out and amp in.
-Chris