Clutch High bite Point = normal, every new owner finds it a bit weird, it is adjustable, BUT be careful if you try this.
Engine Idle = As GM Ballistic writes.
Brakes = Apply Copper Slip to back of the pad. Is it worse when braking at slow speeds? RE; dust, what pads are fitted?
Paint = Front of the car suffers badly from chips, not sure about the bubbles you mention. What year & mileage is your Z? Post some photo's.
Leather = I've been recommended Dr. Leather products but have yet to receive them so as yet can't comment. Read Detailing section, more info there.
Gearbox = A lot of gearboxes feel a bit notchy, more so if you're used to Beemers, do you have any service history with your Z?
Well it doesn't sound like its going to blow up or burst into flames, but it'll be worth finding a 350Z specialist near you to cover things you don't fancy doing yourself. Don't even THINK of going to a Nissan stealership. If you're near Leicester go to Cougar Sport, or Abbey Motorsport 10 mins from J6 on M25 or Horsham Developments can be found at Chieveley, Berkshire, these guys all really know therestuff. I'm sure other members will chime in if you are nowhere near any of these. Hope this helps.