No upgrades available. I posed a while back that mine developed vibration issue after dumping it . Tried Drag Specialty mounts and they were way worse, very hard rubber and shook my eyes out.
You can try to change the mounts but not likely to improve anything.
You need to confirm primary chain is at proper tension, drive belt proper tensin. Then look at steering head, make sure adjusted proper and also look at all engine mount bolts. Re torque all.
Mine imporved a little after i changed the front mounts but could have been due to everthing else I did. such as I found steering head bolt way too tight. Still want to rule out fork issue. and possible front wheel bearing.
As I always preach, You will most likely find lots of issues so do not stop with just one. Check everthing.