I'm with you ICEMAN, I'm in the process of de-bumpering mine. I posted a few days ago about the rear bumper support tubes and whether they can be removed without resorting to a saw - can anyone help?
I am afraid you will need to be creative with the back bumper supports and as Andrea says it will be not very easy to revert.
Re de-bumpering, this can be argued as a period look for going rallying but generally only up to Series 2. For me Fulvia 3 looks best with bumpers for some reason...