I have heard a lot of the ATG and XFR series had a lot of problems when they got older with the screens leaking. You see a ton of them on ebay with bubbles in the liquid that is in the screen on them.
The XT2 that I fixed and sold I thought something was wrong with the screen lighting when I first got it. It would auto dim, and act crazy. In the bios it was called ambiant light sensor. It was some power saving BS. Once I disabled that it worked like it should.
Well I have one E6400 and one E6410 on the way. Have to see how they are when they get here. One had core 2 duo 2.9 the other a i5 2.4.
I have a "few" of the D630 XFR model and absolutely love them (love that tan color scheme too!)! I swapped out the processor for the T7700 with 4GB RAM and an SSD and they will scream! I also have two of the XT2 XFR that is similar to the 18/19 series with a dual core processor and 5GB RAM. I thought about the E6400 XFR, but did not see the need. Since I have W7 Ultimate in the D630, I am going to up the RAM to 8GB.