For my experience, Hasegawa, Airfix (part of Humbrol) and Heller have a great spare parts department, since they've sent me everything i've requested until now....
Revell has gonne down the pit, since now they charge for parts!!!!!!!!!
But not for decals!!!!!!!!!!
And all the others i've tryed, for me, they've gonne sunk!!!!!!!!!
I've got an Academy's 1/72 F-14A Tomcat put aside because they don't even reply to my request for the decals!!!!!!
Never more!!!!!!!!!!!!!!!
And of course, for old manufacturers, no hope!!!!
How can anyone request parts to Kangnam and Fujimi??????
I don't really know.....