Well I have had the 4.1 System Update message for about a week now. Im on 4.0E (Europe) and have Homebrew so I havent dared to update just yet as I want to know a bit more about the update before I risk anything.
I cant run Wii Sports Resort PAL when I use my iso loader. Returns a blue screen with error 003. Havent seen this error before and I have the extra sensor plugged into the controller. I can run Rock Revolution PAL if I just load the game from the iso loader and this game also shows the 4.1 update so I can avoid the update on that game but not on Sports Resort for some reason.
EDIT: I installed Neogamma R6 loader to my homebrew channel and ran the game from this loader and now Sports Resort works fine

And the error I got before was 002 and not 003. So Neogamma can run Wii Sports Resort on 4.0E without running the new 4.1E system update.