Usually on a white sticker on the underside of the tank or in your service record book. They never get much grease on them from the factory. Replace the standard shock and the fork springs, you'll notice a difference. Check your tyres and ensure you have the correct psi. As a rule of thumb if the tuned length and positioning of the pipe has not been altered then no, not usually.
All bikes run better once they've been tailored to their pipe.
We've found that it does vary slightly but the average seems to be between 500ml and 1 litre every 3000 - 4000 miles. Suspension tie rods that go between the top swinging arm mount and the shock absorber pivoting bracket. Usually jacks the back end up by about 30mm and the seat height by about 10mm. If putting a jack up kit in beware of fork sag. A longer gear rod linkage will be needed too which BanditMania can supply.