I found on my M9 that with the new trigger bar a 12# spring wouldn't always reliably ignite hard primers, but so far the 13# spring works great and the trigger pull is quite a bit better than with the 14# spring.
The one thing about this trigger bar, though is that it has a very long DA pull and until you get used to it you begin to wonder if the trigger will break before the trigger reaches the grip. A bunch of DA/SA transition practice quickly takes care of that, though.