I did it myself (with help on the Japan side) bought in Japan, Shipped, Organised Compliance, Rego.
I got a 2006 series 3, Auto, Silver (Sunroof which is a rare option) with 24,000 km, Paid just over 800K JPY, once I paid for the car, transport to the port, and any other fees and whatnot on the Japan side cost 10K AUD. Shipping and Tax was 3200, Compliance was 2K, then 700 for tyres and then rego, So all in ignoring rego 16K. Absolutely immaculate, was was ex company lease car (Nissan financial services)
So yeah 15K is very doable for a V35 anyway. I know J spec,Ben is trustworthy honest straight shooter (He was dating one of my wives friends when he lived in Japan so I know more about him than I should so yeah my wife is Japanese)
If a car is tampered with its going to be on the Australian side by the dealers, cars in Japan depreciate more on age than kilometers, thus it makes sense to wind and odometer as in Australia km are more a determinate of price than age. The auction sheets are very honest, probably too honest if there is an issue they will call it how it is, keeping a customer happy and a relationship solid is worth more to Japanese than a quick one off buck should they screw a customer over. If you end up going with a V35 then get a series 2/3, the interior is much better than the series 1, some decent upgrades.
I have log ins for a couple of the bigger auctions houses in Japan so based on recent auctions here are some examples:
V35 coupe, April 2005 (series 2) Silver Auto, Auction grading 4BB 27,000 KM sold for 554,000 JPY or AUD 6900 (exchange rate now is lousy)
V35 coupe May 2005 (series 2) Black Auto, Auction grading 4CC, 38,000 KM sold for 704,000 JPY or AUD 8700
V35 coupe April 2005 (series 2) Silver Auto, Auction grading 4.5BC 43,000 KM sold for 630,000 JPY or AUD 7800
Shipping, Tax, Customs fees, Quarantee fees, Compliance and tyres 5K-6K AUD. Shipped to Brisbane, southern states cost more (I'm from QLD so it works for me)
I have been told to stay away from the V36 with Hard Drives in them (which is most) as if it goes down the car is un usable and getting a new one is crazy expensive and hard to get, but they are a nice looking car, anyway here are some recent auctions for them
V36 Coupe, Auto Grading 4.5BB 10,000 Km, 2013 2,670,000 JPY ball park 30K AUD
Since your budget is 15K allowing 6K for costs, leaves 9K or 730,000 JPY, so with that as a budget there are no V36 even close, the cheapest is 910,000 which is for a 2007 red coupe, 90,000 km grading 4CC Auto
DIY importing is not that difficult (done three times now) its just emails, a couple intl bank transfers, waiting a few months. Basically this the process:
1. Find Used Exporter to act as your buying agent (I can give you mines details)
2. Tell agent what sort of car you want, send them some money to show you aren't a tyre kicker (for me was 500 AUD there abouts)
3. They will send you potential candidates you tell them how much to pay, they can get cars from Auction, Yahoo Auction (Japan's ebay) from Dealer yard
4. If they have something you like tell them the max they are allowed to bid. You need to factor in auction fees, Japan sales tax, Agents fee (mine is 250 a car) degas charge (100) trucking from auctions house to port. I would allow 100,000 JPY for that. So Your max bid 9K = 730,000 JPY - 100,000 JPY = 630,000
5. Agent will take car of Japan side and organise it all, send you a invoice pay the outstanding. Then will send you documents you need, Invoice, Degas Cert, Bill of Ladding, Dereg papers.
6. As soon as you buy the car, ie Win the auction have the compliance shop you choose to apply for the import approval, they will need details, VIN, model, make etc. It only takes a week or so.
7. Car gets loaded, Get details of the logistics company, when it arrives tell them where to deliver it (charges involved) give them the paperwork they need (supplied by Japanese agent/Compliance workshop) then they will do the rest ie customs/quarantine then pay them and job done, it will be delivered from the port to the compliance workshop.
8. Compliance guy does his thing, takes a week or two, pay him is money usually 2K, get a roadworthy (my compliance guy does it for free) then drive to get rego'ed, slap plates on. Game over
J spec will do all the above and charge you a bit on top, maybe 1-2K, not sure anymore.