Have a buddy who has worked for Directed for years, through their acquisitions of Precision, Orion, a/d/s, etc. I asked him a while back about the PPI 356/355cs vs the a/d/s 346/345cs and he confirmed that they are basically the same.
He indicated that the tweets and xovers are basically identical to the a/d/s 3XXcs. The mids have been changed up a bit with the removable phase plug for the convertible tweeter mount and use a lighter material on the cone.
Also, if you compare the a/d/s & PPI PDF manuals online, they are 90% identical.
Just blew another ID mid... thinking about changing things up and trying the PPI 356cs.