A nice upgrade for your KT-8300. This was made by the well-known FM enthusiast Bill Ammons, who made several different boards for various tuners to enhance their performance.
More info is available here: https://fmtunerinfo.com/AmmonsKT-8300.pdf
Description:
The KT-8300 Dual IF Band Stereo Separation Control PCB upgrades the
KT-8300 to provide a second set of stereo separation controls. In stock
form the KT-8300 only has one adjustment control per channel. Normally
this control is optimized to give the best stereo separation in the WIDE
IF mode. When the unit is operated in the NARROW IF mode, stereo
separation is not optimized. As the NARROW IF bandwidth is decreased
further, stereo separation drops quickly. Four 15 turn sealed pots allow
easy drift free adjustment of stereo separation This new PCB can easily
provide an additional 15 to 25 dB of stereo separation in the NARROW IF
mode.
Shipping included, feel free to make a reasonable offer.