Not sure what the market is in AU for used parts but in the US, here's my estimates in USD...
ECU $400
driveshaft (bad threaded style from 09) $40
impeller $75
For an 09 model, it's almost always better to fix and sell running instead of parting it out. An 09 GTI 155 SE is still worth $5k in the US if in good shape. The used parts generally don't add up to the value of a good running ski(including the cost to fix it) and not to mention all the work to disassemble, clean up, take pics, list for sale, deal with lots of buyers, etc. No thanks, I almost always fix and sell all 4tecs.