Borderlands 2 - Golden Key

Hi,
I got my key with game as i pre-ordered it. In-game it tells you that the items received depend on the level you are when you open it. I am currently lvl 13 and not very far into the game. i take my time and do as many side missions as i can to lvl up, so when is a good time or lvl to unlock the chest ?

As soon as you get stuck on a hard mission then go and get your 2 purple weapons.

They will be at your current lvl.

I am waiting for my 2nd playthru, so prob lvl 35

I've read that doing it at the level cap or at the start of your second playthrough is the best time, but I can't remember the reasons why. It looks like they are going to be somewhat generous giving them out though, as you can get a free one by redeeming a test code on the Shift page, so feel free to use it when you feel is best.

Cool, thnx guys.