I ordered a Powderlites kit for my Nytro and Dave said the Nytro drivers haven't really been a problem. I've heard they have been from some people (maybe just people who overdo a little?). This is a big money project for me so I don't want to change parts I don't need to. But, if I need to, I'd rather do it when changing out the track this summer. Do I really need to change them out or will they most likely last and only really fail under very extreme conditions? Thanks for input.