Poserpro, the differences between EI 4 and the tool kit is that the kit is a previous version of EI. Its version 2.9, which means some of the plugins designed for version 4 probably won't work on 2.9. I've been reading the forums at the site and aside from greater funtionality in the current version (as to be expected), the 2.9 version does not render as fast (also to be expected). The features are not all that different between the toolkit and current version and the differences appear to be for the very proficient who want that extra edge. I'd highly recommend you get the demos and play. The kit has excellant training videos so if you like the interface, away you go. (interface is similar to lightwave). Any models you make in the kit save in .fac format. There are third party disks out there with TONS of .fac models to play with. The old Play version of Amorphium 1.0 and the new EI Amorphium Pro 1.2 will open a .fac and let you export as .obj or whatever. The kewl thing is that the $119 amorphium pro comes free with this. splines, curves, beizer, nurbs, uber nurbs, bevels, birail, blend, boolean, knife, spline, extrude, knots, layers, mirror, vertex .... tons of tools to use in the modeler and the animator seems to have an array of its own quality tools.