bmx, saw your question on CC regarding the lettering on the Firestones. From what I understand it's just done with a white paint marker. I picked up a pack at Walmart literally 30 minutes ago to do the Firestones on my XS tonight.
I don't have them in front of me but it's just a white paint pen/marker from the arts/crafts section of Walmart. They're like $2 each. I bought 3 thinking I'd maybe run out but 1 will be plenty to do the job. I did the "Firestone" at the top and the "F" symbol at the bottom. Came out super nice and kinda adds a little class to these tires.