If you use M3 & V3 right, they can be smaller than M2 & V2 in filesize. With all Morphs injected and that brand-new supercool hires tex, they're memory hogs and lock up my computer everytime. With careful character design, remembering that a full-body length render doesn't need a 6kx6k head map, and Removing the morphs I don't need to use (I almost always Spawn a head morph for my character and Remove everything but the expression morphs), most things run really smooth.