Want to upgrade my Dell CPI laptop hard drive

[Beavis]

I bought a laptop on Ebay and it works well but wanted to explore some options. I want to upgrade the hard drive to 30GB because I read somewhere that the highest it will support is 32GB with the most current bios A15. Do you think this will work? Not sure if it would work since it's a newer hard drive. Some of the drives are ATA-6 and some are ATA100. Are they the same thing? This one is a Hitachi, the 12GB in my laptop right now is an IBM.

http://www.newegg.com/app/ViewProductDesc.asp?description=22-146-032&depa=3

Dell Latitude CPI Pentium 2 400MHZ, 128MB SDRAM, 12 GB Hard drive

EDIT: sry, I think I should have posted in the storage forum.