Glock 21 +2 extensions

[Firepower!]

Hi
My question is for the Glockoholics out there. I want to know how effective is the +2 magazine extensions? Are they reliable since they use more or less the same strength spring?

 

[Sturmgewehre]

I've been using the Pearce extensions with Wolf springs and they work fine. It's my understanding the OEM springs are too weak for the +2 and will cause failures to feed on the last couple of rounds.