I love sauvignon blanc! It's a wonderfully dry and crisp white wine.
Blueberry sauvignon blanc sounds horrid to me, but if you want to try it, you could wait until the kit is done and then mix up a glass with the wine, the extract, and sweeten it a bit and see how it is. Check the SG to see the level of sweetening to add. If you like it, you would stabilize the wine by racking into a new carboy with sulfites and sorbate (maybe it came with your kit- if not it's easy to buy). Wait a few days after the sulfite/sorbate and then sweeten it to the SG that you liked in the sample.