Interesting comments, and here's my angle...
If the budget tyres are correctly speed rated, they're not inherently dangerous, and in some ways there's value to having lower levels of grip when trying to learn the car on a track / an airfield. On an airfield with lots of run off, as long as you keep safe distances, it shouldn't be a problem if you spin. If you run lower grip tyres, you can reach the limits earlier and play on the edge of grip / driver talent with less of a consequence should you get it wrong.
The difference on an airfield, where you shouldn't really be presented with the same issues as the road (random tractor pulling out, surprise wildlife / potholes / debris / oil), is that with tyres that offer more grip, you drive at the same skill / grip threshold, but when doing so you're going much faster, and things happen quicker when the talent bottle dries up.
My first track day in the 5exi was in heavy rain, with low November ambient temperatures. It was a brilliant day for low speed slides, and learning the behavior of the car on the limit.
By contrast, on the road I'd always opt for a premium tyre (and do even on my daily driver diesel tank), as I want to have the best available grip should the unexpected present itself.
That said, 888s are pap for the road, as they're too fidgety (stiff sidewalls) and drone like mad, so I'd go with a set of premium deep treaded tyres for the road, with a set of 888s or even proper slicks, for the track.
As for geometry, I've experimented a bit with my car, and so far my current settings are my favourite.
Rear
-2 deg camber, 30 minutes toe-in.
Front
-15 minutes of camber, and 15 minutes of toe out. Not sure what the caster is, other than not much!
As my camber sweep is very different to the stock 5exi, and when in bump the camber ramps up quickly, so what works for me, may be quite unsuitable for a standard car.
You can see the differences quite clearly when comparing John's photos above, with these that were taken of my car on Saturday:
http://www.photodirectuk.com/www/gal...WRX/index.html