I'm only speaking from personal experience, unfortunately I have friends that have been abusing this drugs for almost 2 decades (none that inject so I can not speak about that).

I might have my terminology mixed up, but there is definitely a difference between crystallised and that which has been cooked (possibly again). Some of it might possibly be myth on there behalf, as in they don't get as bad a "k belly" or irritated bladder after a binge on the latter.

As well as the bladder/ut issues, snorting (anything) also leads to the corrosion of the septum and also the bone(s) that supports teeth.. Basically excessive use leads to teeth falling out.