I purchased my first macbook pro (15") a week ago and unfortunately the headphone jack couldn't hold in my headphones. I took it back to the store and they promptly replaced it with a new laptop, switching out the hard drive for me. This new laptop (I got it two days ago) doesn't feel as solid as the previous one on the bottom of the case. I can press the area above the logic board pretty far down, but the other side is rock solid. Is this ok/normal, or should I try to get it fixed or another replacement? I just don't want to take it in and be blown off. Otherwise I'm really pleased with my MBP; I just wish the bottom case felt a bit more solid. Thoughts?