WDS mode should not affect speed. There is no description about which one you should select in Help? As I know, there are four-address-format and three-address-format WDS and three-address-format WDS...

Is it a limitation by your ISP? Bypassing the router and directly connecting to your modem, can you connect to stream at that time?

Read #8 and #9. http://forum.tp-link.com/showthread.php?2348-Printer-Controller-Utility-crashes-Windows-8&highlight=printer+controller+utility Try if the problem can be sloved in the same way.

Hi Rob, Hardware version and firmware version of your W8960N? Upgrade the latest firmware. Check iOS of your apple devices and ensure it is up to date. Disable WMM on router page.(Wireless---Advanced)

When you cannot access internet with the WDS one, can you still access internet with the main one, WR740? Change a channel on WR740 like 1, 6 or 11 and reconfigure WR941.

Did you read this instruction? http://www.tp-link.com/en/article/?faqid=603