Look canuck, if you are happy, then buy the car.
Your attitude in here is coming across a little rude, and we have all tried to tell you based on our knowledge and experience that a quality R33 GTR priced in the low $30k's is a very rare occurance, and received abrasive responses from you. Walking in to a Skyline forum, and then proceeding to tell GTRGeoff that you "pass on his overpriced $40k GTR" isnt going to get you very far, and shows that you perhaps dont realise that a fully built GTR is very different to your average 33 GTR with wheels and pod filters, and can very easily fetch well into the $40k's and beyond depending on the extent of its modifications, overall condition, year of manufacture etc.
Its funny, you see a few GTR owners that face financial difficulties and have to sarifice the price of their car to move it, and suddenly the market perception is that all such cars should be just as cheap, this is very very wrong.
We have seen plenty of people that have found "cheap" cars, and thought they struck gold and unfortunately the experience has ended in expensive problems, and lots of areas on the car that required attention. People on this forum always try and assist fellow enthusiasts by making sure they have all the knowledge in front of them and know what to look out for.
Reading your post above, it sounds like you are prepared to purchase based on an assurance that street machines has given you that the vehicle has been thoroughly checked/tested. Is this correct? I personally wouldnt believe ANY dealer that "assures" me that the car is ok. For me to have peace of mind in laying down $30k, I would want the car checked by an independant workshop that I trust, and have things like the compression tested performed with me present. There are a number of very reputable GTR workshops around QLD that you can speak to about providing this independant second opinion on the car for you and it shouldnt cost you alot at all.
The final decision rests with you, if you are confident in this car you have found, then by all means lay down the dollars, and if it turns out to be a genuine bargain buy, then kudos to you!
Best of luck