HEY!!Cant infiniti sue hyundai for taking i30 away??

Doubt it and why would they want to? The Infiniti I30 has been out of production for a few years now. The Hyundai I30 is sold in India and a few other countries where Infiniti products aren't even available. Like you said, BMW tried it and you can't sue a company for using the same letter on their car. Now if Infiniti put out a car called the Camry, then Toyota could sue or Toyota put out a sports car called 350ZX they could be sued by Nissan if those were done in the same markets the original was sold in.