Where to buy (car) tires?

I've had AD09s on a ~480ish rwd car, they were brilliant when warm and on track. However, on anything other than a clean, dry road, they're an absolute bloody handful. 1 particular example was me foolishly braking relatively hard with the wheel about a bold 30 degrees off centre on a slightly damp morning. Next thing I knew the car was sideways across an a road and oncoming traffic was looking at me funny. No ABS and having road tyres on the front probably didn't help! But I'd think really carefully about whether you needed those characteristics. I now have a set of track wheels and one of road wheels!