[TSM330i]

I would think you would be able to add a high-flow cat to any exhaust. These would get rid of the pre-cats obviously. I'm pretty sure O2 sims are already being produced by another vendor so no problem there.

As for pros/cons - I'm not sure what you mean.

Cost - Obviously they'd like to keep the cost down or no one will buy them. Right now the only SS headers available are from Supersprint and they cost a fortune.