Knowing the kind of riding you do I'd try to find a used paul turner for under $200.  Anything more than $200-$250 I'd look at an Aaen or DCS.

If you do remember that you need to open up the stinger using a larger diameter tube as they use a small stinger pipe which restricts exhaust and cause piston over heating on long hard pulls.

The Aaen & DCS will work but I'm not sure they'll give you the low end grunt you might be looking for.