Welcome to GenVibe! That's awesome to hear that you own one Vibe and are considering getting another! There are many 2+ Vibe families here, including myself which just goes to show how awesome a vehicle the Vibe is.
Since I own a 2nd gen (2009-2010), I am much more familiar with them than I am with the 1st gens (2003-2008), but from what I have seen on here, the 1st gen GTs require no less than 89 octane fuel. Although the engine is a 1.8L like your 2010 Base, it has different internals (?) that give it more power, etc. which is why it requires higher octane fuel. I'm sure someone more familiar with the 1st gen GTs will chime in with more precise information.
Post some pictures of your current Vibe when you get a chance and keep us updated on whether you get the second one

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