I dont have any problems when flying and carrying an extra battery for my Macbook Pro. I keep it in my bag, the TSA hasn't said anything yet. Though if i carried 12 extra batteries, they might say something.
The 5400rpm vs 7200rpm makes a difference. Not as much as working in the ram instead of swapping, but there is a difference in performance. Whether you need it or not is another story. Though maxing your ram out is always a good thing to do regardless.
There isn't much of a difference from 2.4 to 2.5 or 2.6GHz, though there is a huge one from 2.1GHz (Base Macbook) to 2.6GHz (BTO Macbook Pro). That makes a huge difference. Even 'only' 10% more is huge when it comes down to rendering or compiling things. The less time you have to sit around waiting for it to render/load/compile, the more time you can spend doing work or the quicker you can get your work done.
Kinda. They're both Santa Rosa platform with an 800MHz bus and take the same speed ram (667MHz DDR2 SODIMM). They've got different amounts of L2 cache though, 3MB on the Macbook vs 4MB on the Macbook Pro which helps a bit.
The 5400rpm vs 7200rpm makes a difference. Not as much as working in the ram instead of swapping, but there is a difference in performance. Whether you need it or not is another story. Though maxing your ram out is always a good thing to do regardless.
There isn't much of a difference from 2.4 to 2.5 or 2.6GHz, though there is a huge one from 2.1GHz (Base Macbook) to 2.6GHz (BTO Macbook Pro). That makes a huge difference. Even 'only' 10% more is huge when it comes down to rendering or compiling things. The less time you have to sit around waiting for it to render/load/compile, the more time you can spend doing work or the quicker you can get your work done.