I have 5.1's and went from an ARC VT100mk2 to a ML 335. While I don't know if the 6's are the same, I can tell you it takes a massive tube amp to control the bass of the 5.1's. The ML 335 was a big improvement over the ARC, the VT100 just didn't have enough juice.
The ML is an excellent match with the Wilson's, the only drawback is it doesn't have quite the bloom of a tube amp. The tonal balance is a tad warm, just what you need with Wilson's. On balance I highly recommend the ML 336 or 336. While a massive tube amp will do certain things better, they have their drawbacks as well.