|Unit Classification||Indirect Ground Vehicle|
Chances are you´ll almost never use a piperruner. The conditions to make one affordable are very specific:
1) You need a map which has plenty of funds to squander
2) the area of coverage of the piperruner is proportional to the amount of connected pipes, so if it cant at least cover a whole front, it likely wont be worth the purchase.
3) Many maps that have lots of pipes are not built with them in mind so they get banned, even maps without many pipes see piperunners banned.
4) Setting aside the above three, almost any other combination of units with 20k is better than building a piperruner, they can only travel on pipes, though they are awesome as they can shot down air, land and sea units alike with massive efficiency.
There are a couple of maps designed specifically for piperruner usage, though they are very few, and the map maker often points out it was his or her intention.
Piperunners can't be loaded at landers, even if the lander is predeployed on a base.