I didn't catch that one. No such thing as 150% audio . It's either 100% scoped out or over the hills and far away. That's all good with me. NPC / Swing / Diode / jump'in this and that and it all adds up to the same thing.
I said the PC-122s were pretty darn good loud radio out of the box with a slight tune , I have nothing against all the wham whams and zoo zoo's a guy can do to his radio to make it do this or that. To each his own.
There's a lot of radio there in a small chassie. Although they are no 148/Grant , they can hold there own for what they are.
PC-122s are decent small chassied AM/SSB'er's . Experiance has taught me (especially on these radios) to much is to much. They will run hot and eventually fail when they didn't need to. Those radios set at 100% are LOUD ! Run a box ? 2 to 8 would get job done nice at the 100% , they will do 20 on SSB ,but running a box ? one might drop the carrier down a little for a cooler running radio in the long and short of it.
Your NPC type mod will work as far as running the box goes on AM , but the audio chip and voltage regulator on those radio run side by side and they will get hot to the point of burning you and up , those audio chips ain't cheap either (if you can find them) like I said before , best to take it easy on those radios , there decent and will stay that way while being treated nicely.