I got real lucky in finding a working T43 with 1500x1040 res screen for 6 dollars at a garage sale!

1. What is the maximum capacity IDE/PATA hard drive that a T43 can use without partitioning? I have already updated BIOS to newest version 1.29. Some people say 120 gig but I heard as much as 320 gig IDE/PATA.
2. I got my T43 to normally see 3 gig of ram on every boot but the installed OS (Lubuntu 14.0.4 lts) only sees 2 gig. I hear it is due to the 915GM chipset and maybe no way around. But... if the BIOS sees 3 gig on every boot... is there anyway to "trick" the T43 to see 3 gig after boot is completed?? Perhaps some kind of flash update for the 915GM chipset?
3. The rest of the computers in our household that my lady and grandkids use are Windows systems hooked to a Lexmark x9575 multipurpose printer/scanner/fax. The drivers are Windows XP but refuse to install for some unknown reason onto my T43 using Wine 1.8. Install gets almost all done, then stops and uninstalls. Everything found online says Lexmark will not work... my question - would anyone know of any generic / third-party print drivers that would allow my T43 to print to the Lexmark x9575? Are there any drivers for wireless / wifi printing to Lexmark x9575 using NDISwrapper??
4. Last... but not least... if unable to see more than 2 gig via Ubuntu OS and 120 gig is the max... is it possible to remove the T43 motherboard and replace it with T61 motherboard? I REALLY DO NOT want to loose this great high-res display!!!