Unfortunately the ATO is happy to give you a concession on whether Luxury Car Tax is payable but they won't let you claim any extra GST input tax credit just because it's fuel efficient ...
http://www.ato.gov.a...8276.htm&page=4
Generally, if you purchase a car and the price is more than the car limit, the maximum amount of GST credit you can claim is one-eleventh of that limit. For 2011-12, the maximum GST credit you can claim is $5,224 (that is, 1/11 x $57,466). This limit also applies to cars which are fuel efficient.
