(T) Tyre pressures

My 1.3multijet mk 2.5 seems to have a lot of wear on the front tyres (especially at the outside edges). I was wondering if the tyer pressures given in the manual were slightly low as the engine is heavier than the petrol versions. The tyre always seemed to be low but the garage said the pressures were spot on.
Any suggestions on what I should do - go slower at corners, put more air into the front tyres or get a better brand (year old Continentals).

What is the best tyre for my Punto ( a friend suggested Pirrelli) ?

Thanks
esseffe

Have you had the tracking checked as well?

If it is just the outside edge, then it sounds like;

a) The steering geometry is slightly out, in which case the tracking will need adjusting. However, both tyres would tend not to wear at the same speed, so this may be a sign of deeper trouble within the steering geometry

b) you go around corners too fast!

If the inside edge is also wearing quickly, then the tyres are under pressure. What do you put in them? About 2.1 bar is about right perhaps?