My opinion, that's smoke. The HDMI 1.3 spec increases single-link bandwidth to 340 MHz (10.2 Gbit/s), which is a big jump from the earlier spec, but most of the things that would need that bandwidth are optional, such as deep color support. The chances are very strong that you are not using anything that would come close to exceeding the bandwidth available on your current cables. From a cable perspective, that is all that changes with the various HDMI specs; support for increased bandwidth. Remember, to most A/V retailers, cables are almost pure margin. A store can make a LOT of money selling you 3 super-duper, Monster HDMI cables with genuine pixie dust infused in the copper to improve signal flow and make your equipment sound warmer, less harsh, with more detailed highs
So, roll with your current cables and if, for some reason, they prove inadequate, there's always monoprice