this has been discussed many times.
1) the oem screen has been converted before by others, and you can do it as well.
2) the xenarc screen will probably be better quality and easier to read small fonts in navigation windows.
3) the oem is probably not touchscreen. if by some chance it is, it'd be extremely difficult to get it to work with your computer anyway.
although you could convert the oem screen, you'd probably be better off installing a xenarc/lilliput/whatever