Handling help

My mk3 polo has been lowered a while now, first of all has some 13x6 all round and it handled brilliantly then i put my steels on, didn't handle great but felt ok, now I've got a set of 13x7's, i fitted 2 new tyres and fitted them to the rear, drove like this for a week all was good but yesterday i did my front tyres and fitted them and something doesn't feel right, when i turn quick mainly as speeds over 30-40 the car feels really twitchy almost like it wants to kick the back out or something, tyres are yokes and inflated to 32 psi but to me something doesn't feel right or is it just where the tyres are so grippy the moving is being transferred through the suspension?

I have no idea

Thanks

jason.