...for you not to run Firefox 2.0.0.6.
1.1.4 is ancient. Whilst it's true that you can run anything you like, you will receive a better web experience if you run a better browser.
I've had flawless performance from Z on everything from dialup to mobile phones over GPRS to my Mac on a 20Mbps cable connection. If it's not working right for you, you have something wrong in your setup.