If yo are in Bangkok go to a few dealers at first and see what they can offer. Then go to the motor show (try the last day or two of the show) - they want to capture a few more sales before the show ends. See if they can match or better the dealers offer.
You may get a better deal in a Bangkok dealer than one up country. When we bought our CRV, we got a better deal in Nonthaburi than in Ratchaburi (despite the fact that the owner of the Ratchaburi dealer is an old school friend of my wife).