[Question] What are the differences between 350 TD soles? (David's 6th batch Vs. retail)

Hey guys,

I'm looking for anything that differs between the Davids 6th batch 350 TDs vs. retail TDs when it comes to the sole. I've seen way too much info on the pattern, heel tabs, toe box, etc.. But I haven't heard much about the sole. So what are the flaws? Thanks!