I can sort of understand the civic part. I I've mistaken the old civic for is300 sometimes when I see it's rear end from far away. I think its the angle of the rear pillar that makes the car seems similar to is300.
I remember an article in Car and Driver magazine few years ago where the asked their readers to guess which family sedan is which. They had mostly all manufacturers family sedans pictured with a line underneath each car for the reader to fill in. It seemed easy at first but then I realized it was not, most of them looked somewhat identical. It's no surprise to me that there are similarities with the IS to other cars. Ok, so the Civic, a Corolla are in a different classification as far as cars go but, when these companies know what looks sell they usually tend to have those similarities between them. At least you won't mistake a Daewoo for the IS!