I guess it used about a half a liter in 1500 miles. I checked it cold on the side stand the other day and it was down a couple marks. I previously addes 250 ml about 600 miles ago. The noise is possibly detonation. It does go away. Is sounds like a frigging rock hitting my chin spoiler when I come on to it though. Is that normal? Also, regarding pipes. I asked the dealer and they said there was no mapping or mods. Just put the pipes on and drive it. What do you think of that?
So approximately a liter/qt in 3000 miles. Honestly if that were consistent I'd not let it worry me. Make sure, however, you're not simply refilling the same lost half liter all the time.
These engines commonly don't like to be filled what seems like "full." Try leaving it about a half quart low on the dipstick with a cold engine. Then see if it continues to use oil from there. You might find it has a happy point somewhere around there and the usage diminishes. As mentioned before, however, if it only used a quart in 3k miles I'd not worry a bit. That's a common oil change interval for many. Even if you take the synthetics to 5K that's only topping off once between changes.
If the noise comes on under acceleration and then goes away it is likely pre-ignition/detonation. It can do damage if its extreme. As a point to consider heavy detonation is unlikely on your bike if it's still in stock trim. So if you really are hearing detonation in a cylinder it likely means someone has changed some parts, the bike has had a poor tuning effort, maybe you've got a vacuum leak at the intake or something else is going on. Given the bike's age don't discount some regular service considerations also. Possibility of plug wires breaking down. On rare occasion that can cause an ugly noise too.
Good luck