 The thing burns through the oil.  If you don't supplement it, immediately it wears down the seals and eventually will blow your engine. The thing burns through tires like crazy too. My engine has blown..but I'm not opposed to trying again with another.  I'll just be extra careful about the oil! Also, don't try putting anyone above or below the age of 8 in the back seat.  Carseats don't fit well and neither do legs.