The "S" logo is a thick rubberized self adhesive 3-D plastic with a chrome finish. I bought one for my windshield from Ron Ayers.
Here is the
Emblem, they are $19.79 US + shipping
I'd go for the tank change ($440.87 US + Shipping in Black new) just to get a steel tank. You can find a herd of used tanks on eBay. Be aware though, that the front fender is plastic.