I think you can already guess from the title, but I think there should be a car or another Japanese brand to compete with Hirochi, like the rivalry of Subaru and Mitsubishi. Particularly the Sunburst. I know that Hirochi is supposed to be a little bit of both but I think it would be cool. I have no idea what the name should be, so I may do some Japanese translations research and make a poll for the names that come up.
should be ibishu. Ibishu is literally Hirochi's rival. I think, due to the fact that the Sunburst is heavily inspired by the WRX, and slightly by the Evo, it would make sense if you just switched that around. It would be based on the EVO X, too. this one would have a H4, too, as the Sunburst has a MIVEC like I4 engine.
I would prefer a gen 1 Sunburst over a direct rival. Early Evo's are awesome looking IMO, would be cool to see an older, less sophisticated Sunburst.
Since the dominant vote was neither, (and I don't blame you guys, they are corny) I'm gonna leave it to you to make some names. Also sorry if anyone was offended because I literally just put car-related terms into google translate as don't know much Japanese except for Konnichiwa and my friend's name in Japanese.