understeer when tyres are at end of life
 

is it just me or do you guys fine that when you are getting near the end of the life ( legal limmit + 1mm ) you get loads more understeer

been on the f1s for a while and like them but understeer city again now they are close to death ( in the dry :))

In the dry I find them fine even when they're low on tread, but in the wet they're bloody terrible.

Just bear one thing in mind:
When wet any tyre will offer less grip (especially when worn), hence the natural balance of the car will come more into play (ie front heavy = understeer).
Suspension tweaks like anti-roll bars, stiffer springs, more camber etc, are not as effective (these need the high dry cornering loads to come into play) and so you will get more understeer...
The only way around it (without going silly disconecting the front ARB etc)is, to have a slower entry speed, and gradually apply more power to balance the car.
My experience is that any tyre near it's wear limits, will give understeer to an Impreza....
How worn are your rears? If they have pleanty of thead they will give more grip at the back, and make things even worse for you.