Never seen these before.
Its hard to make out in the pic... but are the large brackets metal?
How long are the post's and are they threaded?
As a guess..If they are metal & pending length id imagine the large brackets will side up underneath the underside of the tower, with the posts sticking through the body and strut brace. The nuts will then bolt down.
Only issue is that if youre putting this on the MK4 youll need to trim the passenger side part of the brace to fit around the bonnet lifter and compromise its strength. Plus the large passenger side bracket will need to have one of its posts removed as the lifter is in the way... so you will have a trimmed bracket with one less fastening point on the tower
Id imagine the smaller brackets attach via the side with the 2 holes and are fastened with 2 nuts, with the one threaded post facing upwards to secure the struct brace in place with one nut per bracket... but they only help to ensure that the bar doesnt bend (if anything). I feel that the most important areas of fastening are on the towers themselves as the brace is there to prevent/minimise the independant flexing of the towers. Perhaps thats why you should opt for the S3 one if possible as it is a direct and secure fit. Only requires 6 bolts, 6 nuts and washers - instead of these brackets designed for the TT.
Either way good luck.
Found this pic which shows a brace on a TT in place.
