sgc wrote:
Keep in mind that duty and GST is only payable on items you bring in to sell. If you own it, you've paid VAT already (and have proof), and you don't look like you're importing bits commercially you'll get away without paying duty and GST.
You won't pay GST or duty on your car, furniture, or any other possessions -- if your "spare parts" are "possessions" then you'll be fine

not necessarily - if you've bought it in the past year you get charged (assuming you're honest and say so on the customs form

). I was charged 10% customs duty and THEN 10% GST on the value of the goods PLUS customs duty on a pile of stuff i brought back over last year. $900 worth of stuff + $90 Customs duty + $99 GST.
theoretically you can inversely not pay (or claim back) the UK VAT but I kind of f---ed up that up when i did it and missed the opportunity to do so..
If I could offer any advice, it would be to buy whatever you are going to and then make sure it looks like you've owned it for over a year remove packaging and sure as heck don't have invoices or receipts for things packaged with them - as long as you've 'owned' it over a year it's just considered a possesion and is not taxed. At least then you can tell them you've owned everything for over 1 year and there's less contrary evidence!