I have been very happy with various Vandersteen's and top 50w amps as long as they have plenty of current. As we know you may as well add another 25-40% to the power rating when looking at good tube amps over SS ones.
It all depends on you room and listening volume. As long as the speaker is easy to drive as a Vandersteen is, the sensitivity won't matter much. IF you pair said speaker with the Vandersteen sub 3, the main amp is only running in the 100hz on up range so it frees up the bass which is a big drag for most amps. I wouldn't discount any easy to drive speaker and yes, bring your amp with you if you are able to for auditions.
It all depends on you room and listening volume. As long as the speaker is easy to drive as a Vandersteen is, the sensitivity won't matter much. IF you pair said speaker with the Vandersteen sub 3, the main amp is only running in the 100hz on up range so it frees up the bass which is a big drag for most amps. I wouldn't discount any easy to drive speaker and yes, bring your amp with you if you are able to for auditions.