nice save there, yeh they are great cars, we've had our 2007 since new and has done 196,000k's on original brake pads, original clutch and basically never had any real problems with it. You do as with ALL new diesels these days have to change out the injectors when they get the milage up and throw up the wrong values.
Cost me $1600 for new Injectors, pipes and all seals from NZ toyota and had a diesel mechanic put them in for me and do a full cleanup of the throttle body etc for another $1,000. (got 180,000 out of the original injectors and they were still within spec)
But considering it pulls the 17.56.2OB so well and carries 8 people and can do about 1,500 -1,700k's per fuel stops I'm not complaining at all.
The earlier D4D motors (07 120 series, 150 series prado, hilux, even V8 cruisers) had bad injector seats / sheets and got blowby from the cylinders which in turn fowled up the oil pickup screen in the sump which in turn made your engine go "bang" and cost you up to $18,000 to fix.
Newer seals not having that problem so as long as you service them properly (thank you crappy Oz diesel fuel) they will last you a long time.
If you are concerned with the diesel still then the V6 motor in them is a great motor and there are owners out there with close to 700,000k's on them and still going strong.