Easy to fix my son has done it. You need to cut back the exits on both side of the silencer box and form new elbows as the R35 is a lot wider car at the rear end. The sound is awesome :p
It's not the same as the one he drove as the original driven one had a Big Veilsde logo above the rear number plate. There were about 8 of these made, some as props for the damaged scenes.