To me the big problem with "starting another bike" is - finding the other bike. If the "right" bike frame fell into your lap this afternoon it would be a no brainer but used bikes in the right frame size can hard to find. I'd be for re-doing the bike that you have. If your luck runs like mine, about the time you finish, your next door neighbor will throw out a like new IHG equipped bike in the perfect frame size.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.