That high profile Vengance has problems fitting under even small coolers. There is no way it will fit under a Phanteks. 8GB of DDR3 1600 is less than $40 though so you could always just replace the RAM while it's dirt cheap.
You sure you want to put a $100 cooler on a $100 CPU? You are not likely to get any more of an overclock than what you have listed. Maybe a few hundred megahertz you will never notice.
You can't take the heatspreaders off without risking damage to the memory module. It will void the warranty as well as being very hard to do without damaging the chip.
Taking the heat spreaders off was easy. I took a heat gun, warmed them up, and they pulled off with the greatest ease. The only "difficult" part was getting off that goop that they used to stick the heat syncs on.
Now I have fully functional, but ugly, RAM that doesn't get in the way of anything