To complete the system I would swap out the dual scan "cs" display for an active matrix "c" one. I did that with my 1400 and the improvement is stunning. Stupidly I never put a bid on a G3 upgrade that was on eBay UK about a year ago and it sold for very little.

However, there is such a thing as upgrading a machine too much and as Quadraman said, for that kind of money you could get yourself a decent Pismo with generally better specs.