It would be nice to have an extra few rounds for USPSA PCC without reloading.  I could swap parts and try it out but I would hate for it to choke in a match.  Using stock spring and adding the extension should have 36 rounds available.  But is the stock spring enough?

I guess the same question for the ETS 31 round mag could apply.

Looking for experience not conjecture...

Thanks in advance.

Well I guess it was too easy to do, so I did it.  The 36 round mag worked flawlessly and I will see how the spring wears.