I really wish I personally knew more about all motor builds. I believe I have seen people use B16 pistons before in order to help raise the compression. If the pistons are in good shape and you're able to, heck, why not use them and save yourself some money. I feel you on the budget part and think it is a good idea that you want to use parts you already have in order to save some. It only makes sense.
I'd personally rather learn about things first before trying them, because think about this...if you were to build your motor, get everything together and as you were getting it tuned BAM! things started falling apart because you were just "guessing" when putting your build together...yeah, that would not be such a kosher feeling. I'm going to ask about your question so that perhaps I am able to help you out further. Right now I would say take your time and do your research so you end up with a strong, reliable build.
By the way, what are your horse power goals?