I had a cat problem with my Titan. The dealer had Midas put one on. Midas charged them 1100 bucks. That f'ing cat lasted about 2000 miles before the light came on again. It was under warranty, just for the cat but not the labor. They wanted 400$ for that. So I said F you.

I got a Walker brand for 520$ and paid 200$ for labor. Rockauto has them for 320-360$. But for me, I like doing business local.

I have put new spark plugs in too. The next parts to replace are the PCV valve and hoses, they are a little oily.