Any Thoughts on a print problem

Model or printer? Usually it's a bit of both!

Looks like that's a big part - is it really the whole length of the bed?? It's really going to want to curl up, so you'll have to manage that.

* Is your printer enclosed to stay warm? You may need to do at least this much to keep it straight.
* Improving the sticking-down (glass+hairspray, abs+acetone mix, etc.) will help up to a point - that being when the part begins to split mid-print instead.
* Have you considered printing this in multiple pieces (e.g. chop it up into layers) and fixing them together with glue (acetone+abs for example, or even just superglue) afterwards? Perhaps this is too audacious a print to start with...

Re image 4, without a reference, it's a little hard to tell exactly which details on the part are intentional and which are printing flaws - could you perhaps post an image of the cad model / STL (or event the STL itself if you're happy to share it) so we can rule out the bits that should be sticking out? My guess at present is something is loose (maybe the hot-end) which is giving you those wavy bits in the middle.

If the layers aren't bonding well to each other, consider increasing the extrusion ratio (either in slic3r filament settings or in the front panel of repetier host) for this part.