The "spikes" were actually supposed to be heatsink fins, since steel holds heat better than aluminum does. Seemed like a good idea at the time, but hey, they still look cool.
Ground down the welds so they look nice, I still have a few more tack welds I need to do on this mount though, then I will grind down the new tack welds and get it ready for paint. I will also be welding the other motor mounts today.