The motherboard will support the 1055T. To check what CPUs a motherboard supports go to the motherboards product page and look at the CPU support list. However you are only likely to have compatibility issues with extremely cheap motherboards.
Whether the 6 core CPU is worth it depends on what you are using the computer for.
The Hyper Transport speed differences won't have any effect.
The Asus M4A88TD-V Evo/USB3 isn't the best value AMD motherboard to get. If you want a board that doesn't support SLI or Crossfire optimally then you should be spending under $100. If you do then you should get something else as the PCIe lanes are split x16/x4, which is sub-optimal, altho you would get some gain.
You might need a 1000W PSU if you want to install four GTX 460s, or two GTX 580s.
I would not choose one from the Silent Pro Gold series anyway as the ripple and noise is close to the spec on full load.
On your current motherboard it would be hard to justify a PSU above 550/650W, but it depends on what motherboard you decide to get and what graphics setup you want to be able to accommodate.