You need to stick as close to 235 as possible to avoid any issues, 235/35 19 is the closest you will get to 235/40 18 as an equivalent.
35 is not silly low and under normal circumstances but with our roads in such a poor state of repairs your rims will take a battering.
you could try rs4 19" tyre sizing but bearing in mind the rs4 has wider arches those tyre sizes may become an issue on the standard width body , there are a few options and it is a few.
35 is not silly low and under normal circumstances but with our roads in such a poor state of repairs your rims will take a battering.
you could try rs4 19" tyre sizing but bearing in mind the rs4 has wider arches those tyre sizes may become an issue on the standard width body , there are a few options and it is a few.