Flight Sim compatibility and configuration

I know that there can be a few configuration challenges for installs etc. when you have FSX and FSX:SE on the same machine. However, am I correct in assuming there is absolutely no relationship what so ever between FSX:SE, P3D v2 and X-Plane. I am purchasing a new PC and just want to be sure that if I install those 3 that they are all fully separate from one another. Also, is there any place that maintains a compatibility check-list for FSX:SE?

Thanks