Factory bikes

This question has been floating in my mind...from some of the aftermarket parts they have on there bikes are they all custom made from the company..such as on travis's old 125's they all had Bill's pipes and silencers ....where those custom made from Bill Cervera or are those the same that joe shmoe could get ? I know they have many parts that we couldnt get our hands on for any amount of money but for the most part of name brand things like there reeds,handle bars, fuel, oil they are all things we can get rite ? Like there race fuel isnt spiked and there oil is the same stuff off the shelf that we can get rite ?

What do most of those pros and privateers use for race fuel ? MR-2 ? its smells so damn good I wish they made a cologne of it.