Hi BCDave, Unfortunately the GPU enablement kit can only be purchased with the initial build as it includes extra supports for the GPU to be held in place. However our GPU kits are designed for high performance computing, GPU based processing and not for the video offloading of remoteFX. If you have 1100w power supplies and 6 fans in the system you could add your own cards and see if they work, it would not be a supported configuration but it may provide the functionality that you are looking for.  
What is it? I have a few T620's that I would like to add a GPU for RemoteFX and Dell says you need an enablement kit purchased at the same time as the server. Since RemoteFX was an after-thought in my case, can I get around this? Seems odd that Dell would make you buy a whole new server just to get the enablement kit.
T620 GPU enablement kit?