Brullen says that they use 304 stainless. I'm not sure if their warannty covers rust tho. Probably not. This is from their website...
Originally posted by Brullen website:
All BRULLEN EXHAUST products are warrantied against manufacturer's defects for lifetime to the original purchaser (warrenty is non-transferable). This warranty does not apply to any exhaust product which has been damaged as a result of accidents, improper installation, or any alteration of the exhaust product during or any time after installation. This warrenty only covers the replacement of the defective product. It does not cover any costs associated with the installation of a replacement product or the shipping of the replacement product.
I'm still going to leave it off for the winter. It is most likely causing a preformance loss due to my current near-stock setupanyway.
Now that I think of it, I sent in my warranty card but never got anything back. Crap.
Thanks again for all of the info.
Later,
Ben 
