lol, wow, first time venturing out into the non-music discussion areas :D
meth some nasty shit dude....I wouldn't recommend it to anyone ever...you'd be better off playing with crack, or just stick to the powder coke.
That said, if you want to experiment, I'd go with the crystal, stay away from any that yellow shit....
It seems like perhaps you are particularly interested in the sexual benefits, which yes, you can get fucking wilder than any of your imaginations....
...get with your partner and have some fun then...just beware, you do a day here and there, then eventually you going on a weekender...even if you recover in time for work (or whatever), the 3 day benders become 5 days, then you're up for a week at a time...pretty soon you have become exactly everything you have heard the horror stories of...and you never see it happening. seriously.
good luck dude.