Why would you want to do this? Even if it folds down, there is all that cross bracing blocking access to the trunk. But I don't think it would fit -- it's narrower, and the rigid back would be too thick. And how would you deal with the package shelf?
I think the seat looks better than the basic rear seat. Cross bracing can be modified and if I mini tub the rear for a bit more meat, fabrication would be needed anyways.
