Hi...i will suggest preamp and converter quality are the items that provide audio quality. Unless you are running more then 24 channels USB 2.0 is still fast enough to do the job. Once the signal is converted to digital its no longer audio. Its merely digital ones and zeroes.Fast communication speed is only needed if you try to run plugins close to real time when tracking, but again, that's mostly the computer speed. If you run a quad core computer, Solid State drives, 64 bit, loads of memory and it has a fast buss speed then using thunderbolt will prevent bottlenecking.