Impulse VS Asuna (or: same car with different names...why?)

Now, please keep in mind that I’m far from having a good knowledge of cars.

I’m driving a Isuzu Impulse and noticed that there are other cars, that are essencially the same, but are named Asüna. I know there are more cars like that, that look the same but have different names (I can’t come up with the names though) So why is it like that?

Also, is there any problems that the impulses are notorious for, and also how much do you think it would be worth now; it’s a 1990 with 195,000 km and I’m the 3rd owner.