Probably way to late for a response, but no, it wouldn't work. You need a Vibe GT ECU. I think you could get away with an 04 ECU in your 03, but the 03 is the preferred model. I don't believe that even a Matrix ECU would work.
2005 Vibe GT ~ Platinum
2006 Vibe ~ Lava, Base, Auto
2005 Corolla S ~ Silver Streak Mica, Manual (Wife's)
A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete fools.