I had SKS chrome plastic fenders on my 8.3, but just moved them to a 7100 as it is taking over my commuting duties. The back was a little tricky, but they attached to a mount point above and behind the brake caliper, and once adjusted didn't cause it issues as the stays bowed out enough.
The front one required some help. The way I found to do it, and had it confirmed at the LBS when I asked them how they would do it and they showed me, was to share the top mounting bolt with the caliper. This requires a longer bolt, and a standoff (or a lot of washers) so that the stay are positioned out of the way of the arm that actuates the brakes. Also none of the included bolts fit the mount point in the bridge of the front shock/fork.
The 8.3 has mechanical brakes, the 8.4 has hydraulic doesn't it? The fit probably will be different for those.
When I had them on they worked great. I've decided to treat my 8.3 more as a "sport bike" for longer/faster road rides, and off road stuff now that I have the 7100 to handle the commute and family rides, so I'm eventually going to go for some of the "sporty" smaller fenders on the 8.3 that clip on and don't have stays, but it will probably be fall before I seriously look into them.