I used hardened AN washers for my spacers. Any good fastener shop will have them. Aircraft shops will have them as well. you need 3mm worth for each bolt, usually two washers. The spacers get placed between the knuckle and caliper where the mounting bolt passes through.
You also need longer bolts. do a search, I believe shaggy posted up the p/n that I dug up for him some time ago.
Don't waste your money on drilled rotors. They don't cool any better, and will require replacement sooner than plain or slotted rotors. Also, both drilled and slotted rotors will increase pad wear. If you must do something to make the rotors look cool, stick with slotted, otherwise, a plain faced rotor is your best choice for a street car.
As far as cheapest, not sure, as I sourced mine through a friend, but Bill J. has historically been one of the best prices around on most an OEM parts.
Also, when you order your calipers, make sure they are "loaded" unless you plan to run aftermarket FSVT pads from the get go.
