So, I've had my i7 for about three days now, and thus far I'm loving it. I'm just curious, though, as to whether there are any actual differences at all between the aluminum enclosure for the 2010 model and the mid-2009 one. For example, I'm positive the lid on my new MBP feels much heavier when I close it / open it than my previous one did, but I can't help wondering if that's just my imagination ("it's new, therefore it must be different somehow"). Having gotten this one as a free replacement for my previous faulty machine (and had AppleCare thrown in too, talk about customer service!), I obviously no longer have my old one, so I can't compare the two side-by-side... so my question is, has anyone who has both models noticed those sorts of little differences, or am I convincing myself there are changes that don't exist?