I'm not sure your actual question, but I was able to fit two bikes in the trunk of my 2012 Mustang. Can still do so in my 2009 Fusion. Can also do so in the fiancee's 2011 Cruze. I know I can fit a bike with the front wheel off in the back seat, as I can also do with two boxed bikes.

As long as you don't buy a compact, you should be able to do so. If you're worried, do as I did when I bought my Mustang and take what you want to see fit in the car to the dealer when you buy it.