Plex emailed be a couple of months ago saying the cheaper version of the SDM500 would be around 500 euros, just with less features and no logging. But generally same visuals and same ecu compatibility

Which would be a good option as it is visually appealing and at 500 euros would be well priced.

I guess you also need to factor in whether this is an additional info display, or a sole dash display as there are then legal requirements. ie indicators, lights, warnings etc and odometer