I'll see if i can answer your questions. Plenty of people will be along to add to my points/correct them :
-You can get a rear bumper from nissan directly and IIRC they don't cost too much, about £200 I think but then you have to get it painted. Keep a look out on ebay as sometimes they crop up on there from time to time.
-I don't think the mileage counter can be changed. I think it can be changed to record miles or km's. For example, and i may be wrong, my understanding was that if a JDM lands here with 10,000 km's on the clock it then gets converted to miles. Once the clock hits, say 20k, that would then be 10,000km's plus 10,000 miles so you would have to convert the 10k km's to miles to reveal the true mileage. Can any JDM owner confirm this or not?
-The 112 limit can be taken off with a HKS speed limiter thingymagig. PM Bigphil about one of these. i think they cost about £200. there are a couple of versions to cover manuals and auto's so makesure you get the right one for your car.
- Satnav and TV will work. In Japan. As soon as it lands in the uk it will be disfunctional. Usually only the screen is usable.
-Importing is worth the hassle if you don't mind no warranty, have a budget of less than £14k and don't mind waiting a couple of months.
Hope this helps.
Sarnie the helpful