Don't do it man, people have literally died from it.. Or they turned into vegetables.. Or they became like crackheads.. Or they developed schizophrenia or some other mental illness and went crazy.. Look it up on the internet, watch some documentaries.. It's really no different than crack, heroin, flakka, bath salts, crocodile or whatever..
Why do you need K2? Can't you just smoke normal weed? Weed is million times better and safe, and the effects last longer too..
I smoked those synthetic weeds in my teenage years, it almost fucked me up.. I started going nuts, and normal weed was never the same after smoking that stuff, it took me at least 10 years to get the weed effects back to normal again, and even now it's not fully the same.. I think that shit changed something in my brain.. And that was just from 1 month of smoking it, few grams in total.. And they keep changing the recipe all the time to bypass the law..
If you wanna fuck yourself up there are faster, easier and cheaper ways, no need to torture yourself year after year..
So many good grow journals here, by the time you're searching for K2 you can just grow some good normal weed in 3 months..