64MB is a bit small to get the most out of the G3.

I can't stand DS LCDs one of my Wallstreets had the 800x600 DS and I replaced it with a 14" TFT (much better) from my spare parts pile.

If I had a 1400c I would probably just leave it as is instead of putting a G3 in it. Sometimes for the money you are better off just getting a newer machine unless the older model means something special to you (or the upgrade is $20 or less).