There is a purpose for saving at the end of TMC. There are like 6 extra figurines to collect as well as a mirror sheild to obtain, but only after you've killed Vaati and saved the file.

Also Vaati impressed me quite a bit after all of those way too easy bosses. Sadly, now that I know exactly how to kill him, he's... way too easy. Damn! I want a boss that's difficult regardless of whether or not you know how to go about it killing it.

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I suggest playing the GC version first... if you can handle the wait.
Why do you want your first experience with TP to be a mirrored one?
The GC version is superior overall - admit it.