The answer is going to vary based on where the car is sold. US we now have three levels of cats; CA, NY, 48 state legal. I had all 4 cats fail on me at about 130,000 miles and replaced them with aftermarket high flow units at about $100.00 US. plus labor. No engine lights or anything. I have one now at 154k that has broken loose inside (my guess is because of the snow and cold shock form the winter) so I need to go back and have the one replaced. Scrap yards are going to charge a premium if they sell them at all since they can get big $$$ for them for scrap. For a limited roadster here in the us Eastern Catalytic has a bolt on system that can be had for less then 600.00 US that has all the pipe from the headers back to the y pipe. They do not make one for the SRT6 which uses a different setup