Good to see you're coming back out. STS has a lot of challengers now locally.
For STS Miata it's Yoko's A052 205/50's. The "tenth" of a second step down is the Bridgestone RE-71RS 205/50. It's still arguable that depending on your driving style one is faster than the other, but so far with the testing it's slower. Only thing to keep in mine is with either tire you have to bring a sprayer when it starts to get 75degrees and above. Long gone are the days that the top tire's "like" heat.
The other options that Sid mentioned are also great options, but noticeably slower. You do however get longer life out of them and they can handle heat.
Fuel tank, Thank you Mazda. 14mm bolt on the bottom of the tank. Driver side before the axle. Easy to access and drain. Be careful not to over tighten when done.