If you arent prepared to pay the price being asked, then the car you are looking at isnt for you. Are you that misguided that you expect to waltz onto a Skyline forum packed with skyline enthusiasts who have invested massive amounts of time effort and money into their cars and proceed to insult them but offering them way under what they are asking?
As has been said, if you were a genuine buyer, you would actually contact the seller and inspect the car first, not 'send a pm' offering some stupid price.
Sometimes, while unfortunate, some sellers are strapped financially and you will find a bargain, but if you want to start insulting people here and telling others that their cars are worth nothing then you really are on the wrong forum.
As for your massive $15k budget saved from doing all the hard work that us Aussies cant handle, well maybe a Honda civic would be more up your alley.