Intresting, you already have a very nice collection IMO.
I have owned a Omega SMP 2254 since new and have often thought about getting a Rolex ND Sub, However I would not want to get rid of my 2254 to fund it, in fact i would not swap it for one. No disrespect to the Rolex it is just if I compare them side by side (which I have done) I still prefer the Omega, even before considering cost and values.
I would consider selling the tudor rather than the 2254 IMO, as they are easy to replace in the future as they are a current model, where as if you decide to buy another 2254 in the future, the values still seem to be on the rise and finding a good one at a good price might be a hard task.
However, if you want a rolex submariner, fair play to you. Go for it.