Immigration lines at NRT have been a 30-45min ordeal my last few times there as they are now getting "serrious" about looking for bogus passports... even a hour on one recent trip.

So, IMHO 3hrs really isn't enough to justify the hassle. Alternatively, I would recommend catching a shower in the Red Carpet room and just kicking back with a beer. It's a really good facility. I find the layover shower makes a huge difference on the other end...

Surf