So, let's assume that the sedan and coupe share the same wheelbase, same 18" wheel size.

Can someone photoshop the two car's profiles against one another?

 

here ya go

 

it seems the is250c is slightly larger than the is250..according to what you say

 

the only real way to see the size difference is by adjusting the pic so that the rims of both the sedan and coupe line up perfectly.... that's assuming that they are both the same size to begin with (ie. 18")

 

i think pnyboy did a good job.. judging by that gif(or w/e) it's as high as the sedan.. is that right?

 

Here are the original pics just in case...

 

yea..judging by the gif i made..you can tell they are quite different in size..the coupe seems to be a bit larger than the sedan..i put the rims at the same size as you can see there..and the distance between the wheels are the same..so the front and the rear seem to over hang past the sedans

 

Those rims aren't the same size. What size are they supposed to be on the coupe? Is that a rendering? If so, the rim size could be made up and unknown.

Matching the known 18" rim -