How would the 4.2L run no muffler no cats with 3.5"exiting side pipes behind the front tires. like this.......

 

Well....You do get more HP, but being in Cali, aren't they sticklers for emissions? Usually 10-20hp

 

Yes they are, but lets just say I may possibly know a guy.

 

Lol, I can't say much as I have run a few cars on the street without cats. Usually you will run "test pipes" to replace the cats, but I don't think anyone makes an off the shelf unit for us.

 

The the car would run better with no back pressure?

 

What I'm thinking I would do is run a exhaust valve that can redirect the exhaust through a hidden muffler. So I can just say that it is a dummy exhaust.

 

Just buy a different car already. The 10hp gain you're likely to see isn't even close to worth the extra noise you would be generating. You bought a heavy, automatic, 4-door luxury cruiser, stop trying to tinker with it like it's something that it's not.

Something tells me you would really appreciate stepping up to the S-Type R.