That 20hp is probably a wash when you add a couple hundred pound AWD system and the increased drivetrain losses.. 

42 minutes ago, ccap41 said:

That 20hp is probably a wash when you add a couple hundred pound AWD system and the increased drivetrain losses.. 

As an axample,

2009 Trailblazer LT w/ 3LT 4x4 option has the 285HP straight six motor and weights 4,523 lbs

2009 Trailblazer SS AWD with 6L V8 has 400HP and weights 4,663

If it was only a 20hp difference I would agree that there is really just a wash between RWD and AWD, but when you put in 115HP increase with only a 140lb weight increase, it is noticeable difference in the driving dynamic.