I think a lot of new Z owners experience this to be honest. It would probably be worse in an EVO or Subaru! The fact you are a female could also contribute, a lot of men hate being overtaken (no matter what they drive) and when they see it's a woman doing so this would probably anger them more. I actually noticed the change more when I starting driving my old Merc estate, it's a more relaxed drive, even though I'm going the same speed, no one is up my bum in town, desperate to overtake me or speeding up when I go to overtake them. I found the Z good on the motorway, everyone assumes you want to go fast, so more often than not, they get out of the way. In the old merc when I'm sitting at 85mph on the motorway (in the inside lane) I find a lot of people (presumably not using cruise control) pass me as they assume I must be going slowly because I'm in a crap car and using the inside (correct) lane. Then a mile later I catch them up when they realise how fast they were going. Anyway don't let it bother you too much, as other say it's just jealously and you soon get used to it.