120/70R17
150/60R17
Hard to say the mileage on any one specific set of tires on either of our WRXs. We swap to R wheels occasionally, so the mileage per set gets blurry.
In our experience - motorcycle tires wear out quickly.
It seems to be a trade off between sticky & light vs. hard & heavy. Yes, tires cost money, but we're willing to pay a few more $ for the performance.