The RS2000 bumper will bolt straight on, however, if you have the standard lights then they willpush on the bumper and the XR/RX lights are slightly thinner height-wise. You can fit either the RS2000 or the Cosworth bonnet straight on too and use a grille from which ever model you use.

This is my old mk5b: https://passionford.com/forum/restor...ral-to-rs.html