If the SEVS list shows a Nissan Skyline then you CAN NOT import an Infiniti G35 instead as they are tested against the exact specific original car. You can import an Infiniti FX50, etc because they are specifically approved for the Infiniti models.
With regards to finding a suitable workshop with compliance for various models, you should search on the following website then call the workshop to confirm as some only do in-house compliance for their own cars and will not do private work for you ... http://raws.infrastructure.gov.au/rawswebpublic/RAWPubSearch.asp
Considering the poor Aussie Dollar at the moment and the rampant disregard for regulations by many importers who massively wind back mileage, import cars with known accident history and other things which are not really allowed, it means that you will be trying to import a genuine nice car but comparing prices to other importers who have what appear to be similar cars in Australia selling for lower prices. What I am saying is that if you are looking to buy a car for yourself then you will get a better car by importing directly but maybe not cheaper than buying locally in Australia, however you will know what you are buying and that it's right. If you are trying to import just to resell for profit then you will find it very hard to buy at the right price to have it landed here cheap enough to make any money unless you are doing dodgy and illegal things too!
Of course this is just my 2c worth on the matter, although it comes from more than 15 years experience importing cars and current experience being my full time job sourcing cars for people all over the world.