Well, aside from the fact that this should be moved into Other Drugs where you'll get better answers..
No, you shouldn't be smoking, or even vaporizing amphetamine. I think it's because it needs that extra methyl to act as a carrier to bring it past the brain blood barrier, but someone please correct me on that if I'm wrong.
Not to mention you shouldn't smoke meth anyways.. it doesn't last long enough, is way too fiendy for even the most seasoned amphetamine addicts to handle and has a ton more side effects than other RoAs. I recommend oral, it lasts like 3 times as long as smoking does.. but the booty bump is the BEST option for speed, IMO. It might sound a bit gay, but you get over it in 5 minutes when you get smacked with a fat rush. It's more efficient and comes on faster than snorting, and lasts quite a bit longer as well.
Meth has a 99% rectal bioavailbility, I'm sure amphetamine isn't that far off. All I know is that you just can't smoke dex.