I have the steel Lotus Motorsport uprights on my car and I have never had any bearing issues. One thing to consider though is the standard rear brake callipers wont bolt onto the motorpsort rear hubs. They have radial mount fixings so that you can mount the front callipers on the rear.
Thanks - I’m using Hispec 2-pots with radial mounts. Bigger issue is the toelink mounting - I have the Lotus double-shear ally brackets on the standard upright and don’t really want to go to single shear mountings.