I don't know about parts for the bike, but I found a way to convince my wife that I needed to buy quality riding gear.
The way I see it there is no ammount of stuff I could get for my bike to equal more than a womans life expenses:
Purses (seperate from clothes because they are $$$$$)
Hair Cuts and colors
Then add in all the BS we have to purchase to make them happy:
Trips out of town
THEN add in the cost of NOT being able to watch what you want on TV but rather:
Will and Grace
Queer Eye for the Straight guy
Also add in how much you have to listen to them talk about:
New skin procedures
PLUS add in how much you have to hear them BITCH about
And boys, in my mind that = a lot of COIN.