Yeah, that's why you want to use the 2 mb size version without the wrapper-installer. Just rename the small guy to utorrent.exe and overwrite the old with the new and launch it directly from its normal location [%appdata%\utorrent], it'll self-update with no fuss at all.
If you launch the small guy from another location it will redo its [minimal] install , asking a few questions before overwriting itself, and you might loose a few settings but not many, it preserves your setup. But it's easiest to just overwrite it yourself and avoiding any sort of install at all.
BTW, to find the small guy inside of large one, open the large one with 7zip; you'll see within a file called "carrier.exe", that's the small guy, everything else is "the installer" crap, which often offers up shareware...just extract carrier.exe, rename to utorrent.exe and do the overwrite - voila...you're updated...with all your settings intact [important if you turned off all the ads.]
I've been overwritting for years and never once seen an ad or any shareware...
Always look for the 2 mb size, or extract it yourself from the 4mb wrapper...