The first engine I ever built was a B230FX+T! Was a great motor but I was forewarned about the relative delicate piston ring situation compared to its true turbo brother. Depending on how much time you have it may be time to pull the head and look for galling and scrapes on the culprit bore. You may be able to do this with a borescope if you have one.
Regardless of the source of the noise, that motor unfortunately is done and depending on the damage to the bore it will most likely need to be overbored in the dead hole and an oversized piston fitted. Depending on the machine shop they may just want to do all of them to keep the block "straight".
If it were me then I would be looking for a nice low km NA block or turbo block and start again. You may or may not want to fit turbo pistons although it isnt necessary and many of us have had successful running +Ts on NA pistons. The real killer of them is extra heat and friction. Id chalk this up as experience and just make sure to be a little more diligent on the oil to help preventing it happening again.
This ofcourse is only relevant if you find a dead piston in there. If its something like Spac said and its a dropped valve seat then thats something else all together and would more likely happen due to an overheat and the head letting go of the seat.