I'm not a 100% sure but I think they are pretty close to the same height. The SS may seem lower because of it's front bumper being a little more aggressive and the 20" wheels that give the illusion that the wells are filled more than the smaller wheels. But then again a lot of v6's come with the 20s as well, so

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As far as getting the ZL1, get what you like and whatever can fit your budget.
edit:
Just reread your post and saw that your 22 years old. Not knocking on your age or anything, just be careful with your financial decisions. In most cases I would say that a 45k-60k car payment burden at that age will usually end up in regret.