Yeah except for you’re wrong...sort of. In fact, special relativity IS all about frames of reference, and INERTIAL frames of reference to boot. Meaning that in non-inertial frames of reference (i.e. accelerating) special relativity does not apply. However, there may or may not be some yet undiscovered principle that prevents a causal-paradox in general relativity and therefore completely prevents FTL travel. At this point, with what we know, it is possible...with enough energy that is.
Things change once you throw out the assumption that the density of space is homogeneous throughout the universe.
Mass=Energy=Spatial Distortion.