I just finished installing the 3rd delete last week and had a very hard time with the installation. My GRP pipe is smaller than the cat pipe, so I need to follow the expansion process. First, I had difficulties expanding the GRP pipe. It was about 2.95 inch wide while the OEM cat pipe is around 3.05 inch. I ended up braking 2 tail pipe expanders before I can expand the GRP pipe to size. The pipe expanders are suited for mild steel pipes, and they don't work well with stainless steel. I had to visit a muffler shop to have the GRP pipe expanded to roughly 3 inch. However, I cannot fit the expanded pipe into the muffler anymore no matter how hard I try, even after I removed the muffler. Again, I had to visit the muffler shop to have the muffler expanded too. The mechanic told me I probably don't need to expand the GRP pipe in the first place, because the muffler pipe is slitted, once I tighten the clamps there shouldn't be any leaks. Anyway, I then finally went back and installed everything. Checked there's no exhaust leak. Took me a very long time to have this sorted out.