I just recently purchased a 3" HKS Downpipe, and an HKS 3" HP Cat-Back exhaust system from radicalride.com. My question is: do I or do I not need a 3" High flow Cat or Test pipe in order to install this system completely? The guys at radicalride say that this is a "complete" turbo-back system and that I do not need a Cat or delete pipe. I know the stock cat won't bolt up to this system, not that I would want it too anyway, and I don't want to take the factory system out and then find ot that I need a 3" Cat or Delete pipe! - someone please let me know!

Thanks guys!

 

I'm running HKS DP and HKS Catback. Bolt right on with my stock cat.

 

I'm running the DP. You don't need a new cat.

 

I am running an HKS DP (it's more like 2.6") and an HKS carbon-ti cat-back and it bolts up to the stock cat just fine. You will get more power out of the exhaust with a high flow cat or test pipe but it will work with the stock cat.

 

Thanks for the info guys! You have been a tremendous help - I have been worried about this for some time now. One more question though - What and Where is the best place to get the High Flow Cat or Test Pipe? I don't want the check engine light to come on - and I seen some Test Pipes that have a "trick" O2 sensor built into them - is that the way to go? On a gooood note - South Carolina has no inspection or emission laws so I could do without it competely!

Let me know guys!

Thanks again!