I have the JB+ on mine. There's a noticeable increase in the pull, especially uphills where I think previously it was lagging a little. The JB3 should yield more than 20-30 hp, btw.. It should be more like 40-50 but the AWD system loss reduces the power at the wheels.
JB+ was a very easy install. It took me 15 mins but I spent the first 13 mins trying Burger's "USB" method. In the last two minutes, I just leaned down good enough and was able to remove the plug easily with my fingers..
The cost was $230ish, don't remember exactly.. A very good mod for the money, IMO..
I'm also on the lookout for a cheaper ($2500 for a rear muffler? It's not made of gold. That's stupid) exhaust and downpipes for the X6.. Coming from an Infiniti FX35.. That was booming.. X6 is so quiet.. Needs some volume
Ege