Dude - stop whining.
You didnt pay for your car.. it is a modded WRX STi - it has soft tyres, you beat the piss out of the tyres and now you want to nickle and dime about the replacement?
Grow some balls and just admit you abused the car a little and that 8000 miles for a modded 4WD car with agressive alignment and soft tyres is good mileage and move on.
In fact, if you try screw Subaru over I will show them the video of you "abusing" the tyres at an autox before the car was 1000 miles old..
So just be a man, buy new tyres and move on.