|What wanderer said!|
No matter what level of wireless security you use, it will never be as secure as wired connections. Our security guy can crack WEP encryption in under 30 minutes and he told me recently that WPA can be cracked too if you have the right tool and enough CPU cycles.
In the same vein. Wireless cannot compete with a wired solution for bandwidth. Wireless has inherent lag/latency issues and cannot provide the same kind of reliable bandwidth as a wired solution.
So, in light of the fact you want security and bandwidth I highly recommend you explain to your client that in this case, wireless is not the way to go.