Actually, the owners manual says to check it a few minutes after shutdown when the oil is warm, on a level surface, holding the bike upright. If you fill to the full line on the centerstand, with warm oil a few minutes after shutdown, you'll be too full. If you do it right after shutdown on the centerstand, you're even more overfull. Engines tend to burn or vent excess oil, so if you're not checking it right you could be adding oil for no reason.
The simple addition of the exhaust won't increase oil consumption, but if you're riding it harder to enjoy the new music, it might.