Ahhh...well, I suppose that is still possible, but I got the impression from the thread on the Spartan forums that all the races more or less achieve FTL using the same principles, just with different methods. Sort of like how in Star Trek the Federation uses M/AM reactors to power their warp drives, and the Romulans use artificial quantum singularities for their power sources.
Or, to use an automotive example, compare a Tesla Roadster, a Mack semi truck, a diesel Volkswagen Jetta, and a Ford Focus. All of them are vehicles, all of them can do 60 MPH down the highway. However, the manner in which they achieve that speed, the range for which they can maintain it, etc are all very different.