AOpen MX3W-ProV Upgrade Options?

I just inherited this machine and it runs fine after installing W2K
and 256mb ram. What I wondered was whether I could possibly upgrade
the CPU and memory, and if so... what are my limitations?

For instance... could I pop in a P3-933 MHz or P-3-1.0 Ghz without any
difficulty? Also, would it be worthwhile bumping the RAM to 512mb?
And how about the BIOS... should I bother upgrading from the OEM
(never changed) to something newer and if so... which version is
stable and what does it offer?

Last question, I have a 10 Gig 5400 RPM HDD in it and virtually no
software as it's basically an email machine and a means for my
daughter to buy/store iTunes. I have a spare 40 Gig ATA133 drive
which I could slave in there... does that sound OK?

Thanks in advance for the help.