|To begin with, it's generally not good to overclock a laptop. Overclocking *usually* causes the CPU to run hotter & laptop cooling is marginal due to the confined space. And of course, the faster you run it, the more power it will use & the shorter the battery life between charges.|
As for the RAM, you have DDR2-667 that runs at 333MHz frequency by default. Your CPU runs at just 200MHz frequency (800MHz FSB) by default. If you compare the difference in frequencies (CPU vs RAM), your RAM already outpaces the CPU by 67%.
In other words, installing faster rated RAM will have little or no effect on performance.