I'd have to agree with my friend Maryka about not wanting to do repeat surgeries if at all possible. I can tell you (and those I drove crazy here) that the psychic weight of knowing you have an aneurysm -- which you do, I think anything over 4.0 cm is consider an aneurysm -- is really weighty and saps you. I am so glad that I had surgery last summer. I was faced with a different situation. Good valve situation with an aneurysm on the borderline. In surgery, the measurement ended up being 5.0 cm even though the scans were showing smaller. I don't know if that is typical, but definitely keep that in mind and perhaps ask you surgeons about that.
Also, to piggy-back on something Maryka said about connective tissue issues. Working with the wonderful Dr. Dietz at Hopkins, I have learned that there are those with BAV who have connective tissue problems. Doctors -- and many still think this is the case -- used to believe the changed hemodynamics from the leakage caused the dilation. That theory has been put aside and now they believe it is basically a genetic problem that causes the equivalent of loose or weak glue in the tissue leading to expansion.
Also, as Maryka mentions, you can have a normal valve and connective tissue issues. So for instance, I've been told that my children have a 50% predisposition to getting aneurysms. I don't totally understand this, but this does not mean that they will develop aneurysms but that they will be in a subclass that are predisposed to them. And my understanding is that this predisposition does not correlate to BAV. They could have great valves, but aneurystic tissue. They could also conceivably have bad valves and no connective tissue problems. Amazingly only 1/3rd of those with BAV (without connective tissue problems) ever need to have their valves replaced.