Hi,
I'm looking at your front-end for hints on another project. I don't need as much bandwidth, so I'm wondering how much an effect the AD4817 buffer has? The AD8337 datasheet does not say much about its input capacitance. Did you happen to check what bandwidth you got without the ADA4817?
[Update: never mind, the AD8337 has high input leakage current (compared with 1M ohm), so the buffer is required].