You know what's funny? Even though these warp nacelles are very similar to the previous version, they are an entirely new rebuild and I was downright shocked to realize how much easier it was this time than it was a couple of years ago. There is a definite intuitive/predictive knack to Sub-D modeling that takes a lot of time and practice to develop, or at least it did for me. It's kind of like chess in that you really need to be able to think multiple steps ahead of where you're at to achieve a winning strategy.
Since we're on the topic, here's a wireframe rendering of the base mesh for the warp nacelle before the two iterations of subdivision are applied: