As a follow up, the 16T sprocket was a great change. Much more road friendly now with a first gear that allows the bike to gain some ground speed and move out into traffic. 5,000rpm is an indicated 70 mph. I think I'm going to try a 43T rear sprocket which will copy the MT 07 stock gearing. By the way the front and rear sprockets are the same as the MT 07. Strange as one has cast wheels and one laced but they are the same.
No need for any changes to this guard (there is enough space for 16t).
1. The gearing can be too tall for city / off-road ride.
2. Opening the sprocket is super tough! No chance without a good compressor and an air-gun!
3. Might remove your warranty.
4. Just leave it as is and rev it slightly on the freeway - it will survive that