I'm gonna appear stupid but what's DD? Urban dictionary suggests either designated driver (no) or really big breasts (girlfriend? possibly...)
DD = Due Diligence.
Of course you have done extensive market research and as a result know that this property is actually worth significantly more than $340k, which is why you would be happy to buy it at that price.
Or your research points to the house only being really worth $320k in today's market, so you would be silly to offer a cent more no matter how much you like it.
Others say it's a PPOR so it doesn't matter. For me, I only like to buy something I know is a bargain and if it isn't one I won't buy it no matter how perfect it may appear in every other respect.
My advice is to know and be confident about your valuations - your offer price has nothing to do with the asking price. Instead, it should have reference to:
a) how much it is actually worth in the current market; and, if you can get it at or below market value, then consider:
b) how much it is worth to you.
If you can get it at or below market value and you are actually prepared to pay that amount, then knock yourself out with whatever it takes to get it. The asking price has nothing to do with either of these two things...