Totally different mate, been there done that got the tshirt, even wrote the fucking manual

To fit the st bumper you need the following st specific items
Fog lights
Fog light surrounds
Fog light loom
Out air temperature switch
Bumper under tray
Wings
Wheel arch liners
Side skirts
You may also need the headlight washer jet covers but these are not st specific as they are the same across the range
You can also use your under engine cover as, again, these are the same across the board
You will also need all the vehicle spcific nuts bolts clips and screws to hold it all together as they use more than the standard fixings

But you can bolt the bumper on to the standard wings and it looks like you've out the wrong bumper on as nothing else fits to it, even the arch liners are deeper and there is nothing to fix them to the bumper with as there is no plastic where there needs to be as its about 2 inches out

The grilles on the other hand, be it the one at the top where the key goes into or the lower one that sits in the bumper, these can be interchangeable depending on which Mondeo you have, and don't forget, the later titanium models also can with st kit on the front, just not badged as st's as they didn't have the same rear bumpers

There are other subtle differences but in sure you will not be satisfied that its not as straight forward as you may think and unless your motor was a later titanium version, what you have said in the above post is a little misleading