I was wondering a few things about exhaust packing:Can I use a different manufacturers replacement packing in my muffler?Is there a brand that lasts longer/is better than others?I currently have an HMF QRS system on my DVX400 and really don't want to send my muffler back to the company for servicing.I read somewhere that you can purchase the packing and DIY but their website doesn't list packing material as being available.Also is it possible to convert a chambered style muffler to a straight through design?Thanks