Bro, all pro-hormones, all "legal" gear, or anything that used to be deemed legal, is junk...I speak from personal experience. Long before I ever started using the real deal I messed with PH's. I put on some size, strength went up but honestly it was nothing that could not have been done naturally and just as fast. The big thing with PH's is how bad they are for you, real anabolics are far safer and more effective. I'm not saying you should get on an AAS cycle by any means, way to young for that, just giving you a heads up.
And BTW, your buddies may have kept all their gains after PCT, but give it a few more wks, I'd be willing to bet that 90% of those gains will be gone shortly.
When steroids were invented in the 30s, thousands were invented but only a few were manufactured. M1T was one that was invented but never manufactured. Since it was never manufactured it was never made illegal, as there is no legal definition of steroid, each individual steroid must be specifically mentioned in the law. Superdrol was methalated masteron, the methalating changed it's properties. It wasn't illegal because it hadn't been invented and since there is no legal definition of steroid, only specific steroids can be banned.
The reason superdrol was taken off the market, probably, is because the company that makes it, is still liable for any damage they cause. In other words, they didn't want to get sued.
Prohormones are different than M1T and superdrol, because they are not steroids but steroid precursors. This means they are the components your body uses to produce different types of testosterone.