I have a bone stock 06 WRX and I noticed the other day when I had 5 adults in my car that there was a louder than normal drone noise that sounded like it came from the exhaust/engine. I drove earlier in the day by myself and didn't hear this sound. The sound was noticeable when I was accelerating anywhere from 2000 rpm and 2500 rpm in 4th and 5th gear on the freeway. Also, when i hear the drone noise, it also feels like the engine is struggling.
Is this normal? Does the wrx struggle with 5 passengers?
thanks.