For dune riding the CPI in-frame drag pipes hands down, if you want more mid-range for duning go with the T5's
Drag Racing I would go with shearer, CPI, Rockets, RDZ's pipe that looks like the rockets (can't remember name, sorry)
Trails I would go with fatty's or T5's either one will do pretty good.
MX I would do Paul Turner Mids or the 2 into 1 dynoport.
I hear the DMC Alien pipes are pretty good for trails and MX as well.
I run CPI's on everything I have.