If you are running offroad then it is wise to keep the seal on the inside.
I am not so into the ceramic bearings. I must say the one in my JP Eagle is running great, even after 15 liters but if it was a good steel one I would be also happy with it.
I know for sure if the bearing got some play I will go for a original steel one, the gain in performance on paper seems to be awesome but on the track there is no difference, for sure if you are no topdriver. Beside that, 100+ euro for a ceramic bearing or 40 euro for an original steel is making 60 euro difference....
Regarding the front bearings that is not making a difference at al if it is steel or ceramic.
I know Boca makes good affordable ceramic bearings but I also have seen some problems with exploding balls which makes me think twice.
Speed is only fiction but a 130+km/h MRS4 is for real.