r/u_StreamerBTW657

I just had my 02 new edge in the shop for a differential leak, and they told me that the breather valve was getting cut off or pinched somehow from my exhaust pipe (due to my car being lowered) causing a buildup of pressure that’s making the diff housing leak. My exhaust is a custom weld job that the previous owner had done, so would replacing it with an after-market piece do the trick? With these cars being modified so regularly Im wondering whether this is just because I have a weird exhaust (especially since my car isn’t that low).