Is there any major difference between Mark X and Mark XI purple ship weapons?
I haven't noticed any real difference. I did have some Mark XI purple beam arrays, but I got rid of them and switched to all Mark X purples (I'm using one type of beam for all hardpoints) and can still blast the hell out of just about anything as effectively as before.
Mk Xi will have higher damage. Not sure if how muchore and if it is a flat bonus or a multiplicator that gets more efficient depending on your other damage modifications and bonuses.
Okay I wanted to know because I switched out my phasers and quantum torpedo for antiprotons and a transphasic to match my ground weapons and the K7 vendors only go up to mark X.