1. This is my 3rd naked bike and 1 UB, will not compare with my 2 scut which is much milder vibration wise. Vibration worst to good, worst is the SYM Bonus 100, 2nd is my Euro 150, 3rd is my Granstar CG 150. And the winner is the Renegade 250. And I'm suprised myself. I'm thinking with a bigger engine, the vibration must be more.
2. I have not monitored fuel consumption on Ratrat mode. But definitely it will be higher than Mugen's 28km/liter on his R155.
3. No I have not experienced any rattles. Chain guard on swing arm near the power sprocket works pretty good. And on the underside of the swing arm, there's an anti slap made of rubber. There's also a chain guard.
4. I have not yet tried it lately But I'm replacing the front sprocket to one size larger to lower engine RPM on my cruising mode. Sa definitely the TS would increase too. But I don't plan to record it anymore. I'm happy in arangkada mode.
5. I have no idea about backrider. I don't ride with backrider, ever... But with the stock sprocket combination, I would say it's pretty robust.