It's most definitely either a-pvp or its most definnitely MDPV. There is many simular characteristics when comparing the two, but also very noticable differences between the two. Atleast to a familar user of both. I'm going to just guess, and say you have a-PVP and not MDPV. Just for the time being because I'm not going to keep saying the a-pvp or MDPV everytime I mention the substance in the post.
I have a feeling that vaping is the most common ROA amoung regular users of the substance. Personally like to smell it myself rather than vape. Usually it vapes really well off of foil and has a very sensitive low melting point. Sometimes, depending on the batch, it might take a couple of tries to catch on how to boil and vape it just right. But those who get this technique, seem to have quite a bit more trouble putting it down. Likely, someone vaping this stuff will continue on doing so until their "stash" is gone.
An oral dose of this, which you'd need quite a larger dose for to have noticable effects, can be useful for a full functional, not so fiendish, getting things done attitude. Like anything, start off low and don't keep re-dosing just because it hasn't quite "hit like you'd like" because that could quickly catch up to up and have you're heart racing like never before. I've seen too many people have that happen to them. Especially with MDPV, but this as well.
I will likely have more later, but I'll see what some others may have to say about the difference between the two (a-PVP and Methamphet). Its been years since I've even been around it and apparently it didn't give me the normal expected effects as it does others so I can't comment in comparison.