Originally Posted by The Dimer

200 cells.

But seriously, the 100 cells should be less restrictive. I belive the anti-foulers keep the check engine lights at bay regardless of the type.

The 100 cells are probably louder due to less restrictions and the performance gains may be higher with the 100 cells but probably aren't very noticeable compared to the 300 cells.

Originally Posted by F.I. Inc.

Great question! Our 100 cell cat is much less restrictive than our 300 cell cat. It is the least restrictive cat that you can use without going to a resonated or straight test pipe. We recommend them in Supercharged applications because they can withstand much more heat and abuse. It will still be crucial to get your air/fuel ratio optimal so you do not destroy them.

The 300 cell cat will most likely blow out in a force inducted application. Now for Turbocharged applications I recommend to get the cat out of the stock location altogether. (For Off Road Use, of course)! This is why we offer it in the lead pipe. By moving it downstream it will take a lot less abuse.

To finish with two points,

1) The 100 cell cat will see a better performance gain because it is less restrictive.

2) You will not get a CEL with any of our parts when installed correctly.

If you have any other questions please do not hesitate to ask.

Thanks, Tony