Well "really fast engines".. The engines don't need to be fast actually! they only need power for take off and a good fuel (yeah I mean amazing not good) because strong engines needs a lot of fuel. you'd only need engines that can actually produce a pushing force against your ship so that it gains speed. But in space that is hard because it's not possible to use combustion since there's no oxygen. (no oxygen no combustion...)
Because, since there is no friction in space (not really any molecules or any matter in space .. well very very few) there is very near to nothing that produces deceleration. Anyway, it's fooked up in space.