X-plane alone runs smoothly and fine, when I try to use pilot2atc it always crashes out of memory. Ideas?

You need to have at least 16GB of real memory.

Then, if still having  this issue, you can try turning down the X-Plane Rendering options that use PC Memory.  That is explained in the X-Plane documentation.  Those that use mostly GPU memory are not usually a problem, but you can try turning them down as well.