Update problem with my Nintendo Wii

Hey everyone,
since I've bought my Nintendo Wii console in September 2008 I didn't have any problems so far.
But, a few days ago I bought Nintendo's newest highlight game "New Super Mario Bros. Wii";
my Wii now states that it required an update to proceed, furtherly that any modifications could cause damage to it. (Yes, my Wii has a Wasabi modchip, though I don't know which one exactly)

Naturally I didn't proceed. Next thing I did was calling the shop I'd bought my Wii from to tell them the problem.
All they stated was 'You may proceed, if you don't have anything additionally installed.'
I responded that I have installed the Homebrew channel and some virtual console stuff.
He then eventually stated that I am to remove those things first before updating the Wii.

So to cut the long story short: How do I completely remove the things I installed then, to be insured that nothing is going to happen to my Wii if I update it?
I'm asking because I think somebody once told me there was a special way one should use to definitely completely remove those modifications.

If you need any further information go ahead and ask; PLEASE help me :(

All I know is that there's no way to be 100% insured your wii won't get bricked if you download this update. Wii that weren't modded to begin with have been bricked after updating, although I don't know how many Wii's this has happened to. Nintendo has offered to replace those who got bricked, but only if they don't find trace of pirating, which they would with your wii. So if you go through with this update you definitely have to say a little prayer before you do. :D Are you positive that you have to update though? I'm definitely going to avoid that update at all costs.

Not that sure; I visited a friend last weekend, he hasn't got a modchip and had bought the game.. HIS Wii requiered an update.. So I thought mine would probably too :/ guess i've got to actually try it first

Then tell me, if you are not going to update your wii: granted that your wii wants that update once you insert the game, what do YOU intendo to do then?

Isn't there a 'safer' way to update? like downloading an modified image of that update which you can freely use?

Which version are you on currently? If you're on 4.1 (4.2 is the latest) you won't have to update

Well, consider I have it like a year + one or two months; eversince I haven't updated the Wii, so the possibility me having a newer version isn't very high.
But I'll look it up later, the Wii is at my friend's by now.
Thanks for helping me out by the way :D
Regards

:bou::bou::bou::bou:, seems to be V3.2 =( What shall I do?