It is really annoying but not something thats suddenly going to have a easy/inexpensive fix.
It isnt the computer, it'* the memory thats burned into the ROM. The program is finely tuned and so many variables that work with each other. Because of the finesse and dependency of how the sensors work with each other, altering anything is going to put it into a tizzy. Dealers can't even alter the program. If a PCM falters, you replace it.
Your not going to run our LD8 with a LS1 PCM unless you can replicate the original program and have vast engineering/computer knowledge to reset all sensor interactions as you start tweaking. People like Chrfab of Cali, or Mallet Cars can fix you up with a Magnetti Marreli PCM and do such. I spoke to Mallet years ago. Drop the car off for 2 weeks with 5 g'* in hand and they can fix ya up.
DOD is a bad idea for aluminum blocks, which has been pointed to by many as a primary cause of localized heat and head warpage and snapped head bolts common to pre 2004 NorthStars with DOD.
The limp home mode is not a "severly detuned" version of anything. It uses ignition and fuel controls programming like DOD, but from there they go totally different paths. The limp home mode program is in fact much more complicated and allows 4 opposing cylinders, switching off alternately with the other four to fire one cycle, flush air without spark/gas the next. On a side note here, I have talked to several GM Service Techs, one Manager, who say more than half the engines run in the limp home mode suffer moderate to severe head damage anyway. They just never run right again.