i think you are worrying too much about this shipment. sure it is confusing and there are agents and customs brokers to help with customs clearance but from the sounds of things you do not need this as you are only importing one set of wheels this is quite small. i suggest you send your goods with post as that would be most economical for you. if you were to go with a courier such as dhl, fedex, ups you will pay a lot more for their services especially if you do not have an ongoing business account with them. their services include tracking, clearance and door to door delivery. packages need to be declared for customs purposes and the sender can declare it as a gift, sample of non commercial value (ncv) or goods. i guess real businesses can be reluctant to make false declarations. anyhow you are only importing a set of wheels it is not a big deal unlike you were bringing in a container or half container of wheels. customs knows that a quantity like that would be for commercial purpose. duty/tariff/gst can be owed to the government should the commercial value of your goods exceed the limit allowed as free. should check with customs agent on the limit.