I spent about that much a few months ago when i bought redline engine, tranny, diff and diesel injector cleaner for my 4x4.
The diff and tranny oils work great but i would spend that much on engine oil again on a diesel as you need to change it every 5000-7000km.
The diesel injector cleaner works great and the redline dealer was telling me alot of porsche owners rave about the petrol injecotr cleaner