I bought a 2016 QX50 AWD a little over a year ago through a guy at the auto auction. I actually wasn't looking for another Infiniti because the last two cars I owned had been Inifinitis (a 2012 G37 Sport Sedan and a 2003 FX35 Sport). But this QX50 only had 5,500 miles and I did love both of my Infinitis (especially the G37 Sport that my wife now drives - it is a crazy fast, nimble and comfortable), so I bought it at a great price. If you've ever bought at a big dealer auction like this, one thing to know is that you can sit in the car, start it, inspect it etc. but you are not able to actually test drive it. So I had never driven a QX50 before, but thought it was no big deal because it's basically the same engine and underpinnings as my G37. But just like you said, when I first drove it, I could not believe how much slower the QX50 felt than my G37. I know both engines have approximately the same power and torque. The QX is around 300 pounds heavier than my G so that is part of it. The only thing I can think of is it is in the gearing or shift points between the two cars. It is a pretty dramatic difference. But I will confirm that the AWD is a beast in the corners, especially when conditions are a little damp.