My project had a lot of comps and high res assets. I think the longer render times it was estimating were a result of After Effects hitting a particularly processor intensive part of the animation. I cut the motion blur samples by half and just let it render and the time slowly crept down until it finished eventually around 4 or so hours total. I had already tried every render setting, rendering multiple frames on and off, allocating more and less memory, opengl on and off, etc. In the end, I think it is just time for a new machine.