Side skirts are tiger sealed on along the top and an utter twat to remove lol for the front bumper jack the car up take the under tray out from the front bumper and look up you'll have perfect access to the bolts under the wings.
Rear bumper has 2 bolts either side the inner rear quarters 2 at the centre where the boot opens then one either side inner wheel arch and a strap from the middle of the bumper to the spare wheel well.
Good to see a mk2 on here usually nobody gives a shot about them on here lol I've had loads of st's so I'll help you as much as I can but I don't come on here much these days.
I've got a mk2 zetec-s now that I've spent a fortune on lol it's only a 2 litre I got sick of fuelling the st but it comes from factory with the rsap kit although it's mostly made up of st200 parts now.
Good luck with the project