There isn't any real noticeable difference in competition level between 2nl and 5nl. So it matters on whether you are beating the game at 2nl over a significant sample or not. If so, then you should be able to do the same at 5nl. If not, then you definately shouldn't move up as you aren't a proven winner at the lower limit.

You have enough buyins for 5nl, but you have to have a stop-loss in place in case you go on a tad of a downswing. i would say that if you hit $95 or so then you should drop back down to 2nl, IF you do decide to give 5nl a chance.

I'd say if you feel confident enough to go ahead and give 5l a chance, as it isn't any different than 2nl really. However, you may find that over a significant sample you aren't a winner and you lose more money losing at 5nl than at 2nl. So, to be honest, if you haven't put in alot of hands at 2nl and have a decent winrate than it obviously can't hurt to play 2nl and get more experience cheaper.

It's really a matter of what you feel like doing. Just remember to make a plan and stick to it, and drop down if your BR falls below your stop-loss.