I have seen them in cars already. They have some impressive numbers. But a couple of drawbacks I see right off the top of my head. First is their size. Each cell is vary odd sized. They wont fit in normal situtations at the same voltage with nicd, nimh, and lipos. Also the voltage output. They are less than lipo. Since voltage is very important in the rpm department this would be a major set back. Now the good thing is the "C" rateing. 30 "C" is awesome. Also the chargeing is very good. However my lipos dont take that much longer to charge and they fit with higher voltage. The Li Ion battery is going to be one to watch for sure but right now the advantage goes to the lipo. Li Ion needs to work on the size of the cells. If they can get it down to the point of 4 cells in the size of a stick pack then they will have a possable cou on their hands. Right now I have 6 cell lipo packs that fit in a normal battery slot.