The 3.6 didn't come along until 2012, my dad recently got a 2012 with one of those. Makes a little over 300 HP, it's an impressive engine. The 3.9 came along in the 2007 models.

The only V6 the 2006 model had was a 3.5L, and it's very different from our 3.8's. Still OHV, but it's got variable cam timing and other goodies. Peak power output is around the same as the 3.8, a tad more HP and a bit less torque, but it carries the power through a wider range of RPMs. Slightly better fuel economy too.