iPhone：哪种技术对于更快的蓝牙更有用？

I'm adding peer-to-peer bluetooth using GameKit to an iPhone shoot-em-up, so speed is vital. I'm sending about 40 messages a second each way, most of them with the faster GKSendDataUnreliable, all serializing with NSCoding. In testing between a 3G and 3GS, this is slowing the 3G down a lot more than I'd like. I'm wondering where I should concentrate my efforts to speed it up.I'm adding peer-to-peer bluetooth using GameKit