if you've worn the inside or outside edge of your tyres out in no time at all its because you havnt had your tracking done after changing the wishbones. i made the same mistake.

this may cure the screeching but most cars get tyre screech in car parks and on roundabouts and tight corners generally.

have you lowerd it a lot as that will increase the negative camber adding to tyre wear and possibly tyre screeching.

alternatively its cheap shit tyres causing the squeek.

either way you still need to get your tracking done!!

EDIT. What lower arms did you fit? rule of thumb on an escort is always use ford lower arms as they last an awfull lot longer than aftermarket arms!