My Traffic 6/ UT2 Question

Hello;

Im thinking about getting either one of those two programs. I have a few questions: My main reason is to replace the IVAO MTL file because I only fly online either on IVAO or VATSIM. With either one of those programs, will I be able to delete IVAO MTL a replace it with one of those two programs? 

How is the performance of those two programs? 

How big are those two programs after install? 

Thank you very much.