Not a good idea for 2 reasons.
People will be looking for the price of a specific car. They will have to trawl through a lot of posts to get any info, its useless.
Secondly, the first few days of new price list is crazy yes, but short lived. People will still create a post of their fav car or manufacturer and like minded users can easily access the info.
Trying to force everyone on to one post, some people will not be happy.
I dont care either way, but I quite like the unbridled carnage as folks get excited, its like Christmas Day for some folks.