[mike100]

The making your car smell comment is what I take to be when you stop at a light with your windows down and you choke on your own hydrocarbons...

I ran the Z06 cats because:
1) I already had some laying around.
2) they are fairly compact for a 3" catalyst.
3) you know they have a lot more precious metal content and do a better job of converting the pollutants than some universal hi-flow mini cat.
4) oem cats don't usually clog and break apart at the slightest hint of rich running or minor impacts with speed bumps. I thought it was the best catalyst for the application regardless of cost (which happened to be cheap since I had a pair).

I also had some LS2/LS3 catalysts too, but they are flat shaped and I thought it would be a challenge to fit those in the C4 tunnel. People have been giving them away since the LS2 came out.