Just noticed this in the Bard guide:
Perform styles that use instruments: These perform choices carry the obvious disadvantage that you need to use an instrument. This requires that a) you actually have the instrument available, and b) that you use your hands to play the instrument. These are some pretty significant disadvantages, so in general, I don't recommend this as your primary perform type. However, the advantage of this style of perform is that you can get a masterwork instrument, which gives a very nice +2 bonus that stacks with pretty much anything.
What +2 bonus do I get here? With my Perform skill? My spell save DC? D: