sabersupra;1032218 said:I use a Randon Technology Cat, 4". I baught this years ago and paid big money for it ($500). I am not too sure of what is being offered now, but 5 years ago, this was great but now this is way too expensive. The design that I purchased looks like a test pipe but is really a cat. After a few years the element blew out of the cat itself and into my exhaust. That was not cool. It would have been a good idea if the body was 6" diameter and the inlet + outley were 4 ". This way the emement inside would not be able to go anywhere. That's my 2 cents.