Hard Drive Replacement XPS M1210

I bought an XPS M1210 about 9 months ago and I love it.  At the time the largest 7200 RPM hard drive available was 100 GB.  This was not large enough and I went with the 120 GB 5400 RPM hard drive.  Now there are two great 7200 RPM notebook drives available, a 160GB Seagate and a 200 GB Hitachi.  First, are there any recommendations as to which drive is better?  As far as I could tell, the 200 GB Hitachi sports a larger cache, 16mb as apposed to the Seagates 8mb.  Is the extra 40 GB and 8mb cache worth the extra 60 dollars it would cost me to get this drive?  In all reality I don't need larger hard drive then the one I have now (120 GB) but I believe I will see a significant performance boost from having a 7200 RPM drive.  Am I correct in this assumption?  Finally, does anyone know where I can find instructions as to how to remove my current hard drive?  Thanks for any input in this matter.