If you are importing it to sell later, then I would not mention that anywhere. DOTARS will not like that much!
If the bike is arriving next month you may already be in trouble. DOTARS can take weeks to process the approval and you cannot import the bike at all until you have approval granted!
If you have owned it for over a year overseas and have evidence of this, then Personal Import is easiest and fastest. If not, try for a Letter of Compliance option since that model was sold in Aus. Discretionary would be a last resort as you would need to have a really good reason for it to be granted.
Be aware that with the importing hassles, registration/compliance expenses and duties/GST it may actually be a better option financially to bring it in on a carnet then export the bike again and sell it at home. Or even buy one here and sell it when you leave.
Melbourne - Adelaide - Uluru - Great Central Road - Fremantle - Nullarbor - Adelaide - Melbourne in a $1000 Mini - May 2013. We did it!