Lasernigel,
FS's own ATC will interact with the PMDG 737NG in the same way as the Concorde and A330/40 add on's.
I found the PSS A340 very disappointing - lazy panel, poor VC, buggy, poor frame rates, exterior model average....
You'll be impressed with the PMDG model though, I'm yet to find someone who isn't.