hey andrew, because a vq30det isn't 15% larger capacity or 15% more powerful, legally you don't need a engineer's report, but it does give some peace of mind. the problem you do have is that you can't put an engine in your car that is older than your car, so you would need to right out a receipt with '03 on it . putting a different auto behind your engine is going to be very difficult.
p.s. i couldn't get that number, i'll try again tomorrow. nathan