About as much as S-Cab does (I'm still working on Scale Sand). The thing about balance that excites me the most is the possibility of removing weight from an engine. Not all of the weight, of course, but enough to provide a little more room for electronics and yet still have enough ummph to hump the proper load over a hill. A lot of models are over weight (too much fast food?). This includes cars. Calculating scale weight is tricky because you cannot scale physics... yet (I'm working on scale molecules too - is there a good patent lawyer in the house?). S-Cab is exciting because it effectively divorces the wheels from the rail in terms of electricity. So on a hill you could use rubber rail if you could find such a critter.
Did I tell you I found my Trout Creek model of a C&S Cattle Guard? Step one done... check!