I've used the S&S header, currently 399.95 US dolares at Cip1.com, and had
good success, for the money. The fit and finish was not great, but it served
me well on my Mule (beater, hard core mountain goat Syncro.) Last plenty
long time in SW Colorado and had a nice deep rumble. Don't know where you
are, but this is one of those regional things. That S&S wouldn't last long
in the east, I imagine. I had mine on there (two different 2.1 engines, same
Syncro) for ten years. Never a single problem. Surface rust, yes, but never
any holes.
If you have the $, the SS would be the way to go, but how long do you think
that 2.1 has before it blows up? Bwwaaahahahah.....
Just throwing out an alternative that won't break the bank and not trying to
start a sword fight, though I could use the entertainment.
Miguel