Sanjaya,

Icom IC-R75 (R-75) Performance Upgrades by Kiwa Electronics :
KIWA = http://www.kiwa.com/R75.html

#1 Must Do = Kiwa Synchronous Detector Upgrade

# 2 Should do = Kiwa Audio Upgrade

# 3 Worth doing with #2 = Kiwa High-Fidelity Audio Filter

# 4 Do only 'if' you are into AM/MW DXing then get
the "Full" Mod Kiwa AM BCB RF Attenuator Disable

# 5 Worth doing 'if' you don't like play with the Twin PBT
and simply want to select a Filter = Kiwa R75 Filter Module

My Icom IC-R75 is a few years old and has the original Kiwa Mods :
* Kiwa Synchronous Detector Upgrade
* Kiwa Audio Upgrade
* 3.8 kHz IF Filter Upgrade for 450 kHz AM-Sync
(not available any more)

hope this helps ~ RHF