I've got a DX-398 that I use primarily for AM DXing, often while
traveling on business trips. With that in mind, I'm considering
replacing the stock 4.8khz IF filter with either the Kiwa
3.8 filter or the more expensive DSP filter modification from
WX3G.

Details on the DSP filter can be seen at:

http://home.earthlink.net/~wx3g/

Just wondering if anyone else has compared these two
options?