f7 or dynoport

i'd say thats sand/drag based
you'd need to completely clean all mud/dirt off, then completely dry it after everyride, for any oil to work on a trail machine

And the drag pipes don't get hot enough to burn off all the "old" spray either from the last time that way it'll always have a little oil coating the pipe too.
 
When I got my dynoport it came raw. I tryed the "oiling" tech. and didn't have much luck with it. I sprayed the pipe down then rode it and got it nice and hot then let it cool a little and sprayed it down again. It kept the pipe looking nice until I didn't spray it down after one ride. Then it rusted. I had enough of that and sent it off to get chromed.
 
to install my f7 i had to remove the front engine bolt and loosen the other two to lift the front up just enough to get the pipe in. if you hold your tongue right and wiggle the pipe enough, you will probably get it to fit without going to that extent