I have Content Manager, and I like how it allows you to move freely with its showroom. However, the quality of the graphics is very poor in comparison with AC's stock showroom. I have not made any research on custom showrooms.
OH MY GOD! DUDE!!! What mod do you used for that screenshot!!!??? Looks awesome! (also the livery is neat btw). I have several showroom addons but none of them looks like that. the background is really nice.