Chrome Extension for iBroadcast.com that forces the default streaming bitrate to 320kbps if "Original Bitrate Streaming" is not selected. Requires premium account to work. The player still shows 128kbps but you can actually hear the difference (or inspect the page source and see there).

Important: This extension requires a premium subscription to work!

Disclaimer: I have 0 experience with javascript or chrome extensions, so this is a cobbled together "thing" that just happens to work. Use at own risk.