You probably won't have much luck getting Mobil 4T at cycle gear. They have a lot of good synthetic oils, though, most of which are cheaper than the 4T. I used Amsoil full synthetic 20w50 on my last oil change. I've also used Mobil 1 20w50 full synthetic oil for cars and sold a hand for the 4T - no difference in operating temperature or operation that I can tell.
It's definitely worth it to replace the crush washer - I ended up ordering 5 of them from my dealer so I wouldn't need to worry about having one. You don't
have to replace it if you don't have a spare, but it would be something to remember for the next oil change
Sorry - I can't help with the fairings (don't have 'em, don't want 'em :razz: )