All of the blogs I have read suggested doing this first. The IVA manual is really vague, but there is an excellent guide on the purplemeanie blog – including which way around to put it (!!) and how to glue it.
I masking taped up the body for some protection, as suggested. I had a go at putting some cardboard on, but then realised that it would probably get in the way, so left that off for the moment.
I found that I could get the trim on entirely without glue and cutting the back, which is great. I then used superglue (which is apparently what the factory build guys use).
One other thing to note is that the trim won’t go around the left hand bracket for the upper wishbone in one piece as the bracket is next to the bodywork, you will need to have 2 peices. Also, because of how close the arm is to the body, there are gaps, as you can’t get the trim fully around.
This is a bit annoying, as I think the trim looks great all the way around and actually enhances the look, so it would be nice for it to fit all the way around. That said, I probably will never notice it it in a few weeks.