[Elecraft] KSYN3A and below 490 KHz?

[Harry Yingst via Elecraft]

I ordered a pair of the KSYN3A boards because mainly I have an interest in below 500 kHz.
I already have the KBPF3 General Coverage RX Bandpass boards installed in both my receivers.As I understand it I will need to use the RX & AUX antenna inputs.

Is it possible to move the lower limit down (lower than 100 kHz) or is is a constraint of the HW?
Will there be a Mod to the KBPF3 to allow it to work better below 500 kHz? Thank you