Funnily enough i just posted in the Bugatti Veyron thread about this car. I just read that it is lapping Hockenheim 2 seconds faster than the Veyron which in my book is incredible.
I think Nissan don't want people modding it up because it's already tuned on a knife edge and unless you know what you're doing you will ruin the car. To be honest by all accounts the car is so perfect there's not a lot you could do to improve it anyway.
Even Nissan technicians/mechanics won't be allowed anywhere near it. Specialist service stations with trained mechanics are going to be set up especially for the car.
Anyway it's sounding like this could be one of the best cars ever made if you are to believe the hype and at just under £60K (i believe) i don't think it's overpriced, japanese or not.