Yes, it will update you to 4.1 I've done this to 5 other wiis and that guide works great. Preloader is a program that starts before any wii stuff starts and is a great safeguard against stuff like disk updates.
Follow the guide TO A T and it will work great for you. Be sure install the patched 60 first and never uninstall it or you will brick.
Also I have lots of backup loaders on my card but all I really use is neogamma rev7.
Hope this helps. (Careful with double posts btw)