Every bike is different even amongst the Rockets. As for vibration, my 2015 is smoother than my 2013. And any vibration only seems to become a issue starting at 75-80. Clutch rattle is only at idle with clutch out...learn to ignore it. Fuel gage...who really needs it if it fails or is slow as long as the odometer works. Rear tire life....I had no serious expectations of longevity with the weight and torque. I think tires are cheap compared to my truck. Learn to take the tire off yourself and then taking it to someone good to change it for around $50. Keep a spare replacement around. I don't even know about the starter relay delay unless you talking about the time for it to cycle and the fuel pump to pressure up. Never been an issue. Screw the mileage, enjoy the power and the torque, try not to worry about the things that might go wrong, have good road service plan, keep you maintenance up and enjoy the ride as long as it's running good. Just my thoughts after owning one for several years...the forum has help ease the pain a lot.