There's no washer, I pulled the exhaust off my '11 and there was nothing there.
I'm going to dremel the bottom of the air box to get that pre-filter tube out of the way, but that's about it for the engine until I either buy a carb or jets. My air filter is coming in this week sometime, but I won't install that until I have more stuff to throw at it. My Multivar hopefully will make a difference. If not, I'll try some lighter DR pulley weights and see how that does.