I am upgrading to LiPos in June for my B-Day and was wandering if you can tell that a hardcase LiPo pack is puffed when it puffs or does the hardcase not allow you to be able to see the deformity?

If you can't tell from the outside, how can you tell a hardcase LiPo is puffed?

How puffed is "too puffed?" I see people driving with slightly puffed LiPos occasionally and they say that the battery is totally fine. Is it or are they just not being safe?

yes you can tell if a hard case is puffed. If you can rock it back and forth, even a little, on a flat surface it's puffed. Are they still safe to use if they're puffed, yes and no, that's a pack by pack decision and there's no set guideline that can be given, IMO.

I've seen some REALLY puffed packs live for a long time though.