while I can't speak to the Levinson component I would advise (having owned a variety of Bryston amps) I would not go for the "ST" version. If you are looking in the $5K range then look at the "SST2" version as they will be a better match with the B&W speakers. The "ST" models are 2 versions older than the current "SST2" model designation.
An alternate choice would be higher powered Classe amps.
An alternate choice would be higher powered Classe amps.