Well if the pistons look terrible, Then most likely the block is shot as well. I take it that is why he recommended a short block, (which includes the pistons, crank, all bearings, all rods and it is all pre assembled.)
A base map from full blown motorsports is purely for first start and driving very carefully to an experienced tuner. They are ball park maps, meaning the AFR will be close but not exact. Full blown or any other manufacturer cannot create a one size fits all tune as every car is a little different. In turn, you more than likely did the damage by getting on it without a car specific tune and you managed to lean out your engine causing large amounts of detonation.
With that said, It's time to do the clean up. Go with the short block, If you can get a fully built shortblock from Full blown or Crawford ( I am not associated with either company) or any other company with decent reviews, then go for it, pull the trigger.
Also, this time around, drive it very slowly, out of boost to a reputable tuner after your new engine has been assembled. If you need help finding one near you, let me know and I can find someone for you.
Let this all be a very expensive lesson but look at the bright side, you might get a built short block out of it.
