Filters, Audio Mod Query

[hwardsil@wolfenet.com (Ward Silver)]

Question 1 - Are there replacement filters for the FT990 available from
any third parties?  I'm particularly interested in a 1.8kHz sideband
filter, and possibly improving the stop band rejection in the 500Hz
filter.

Question 2 - Is there a published mod on increasing the audio output
level?

Thanks and 73
Ward N0AX