Ernst is funny. To me, asking a bunch of guys on the internet about aftermarket add-ons is kind of like asking who you should date or marry. It is a personal sort of decision. In my view, there isn't a single part of the kit that is significantly deficient. Well, maybe those door safety catches, I left those off. Most of us went with the Matco axle, but I've seen knowledgeable folks argue that the stock axle can work fine, if set up carefully. So, who's to say? Some will say you need to empty the bank account on chrome door handles and carbon fiber cup holders, and others will say you need to have your head examined if you do. Great thing about experimental aviation is you get to decide for yourself.
You will have a great airplane no matter what you decide. Enjoy the build,