I've thought a lot about a R150F swap, havnt researched it much yet.
My concern is on the ECU swap. Will it be compatible with my URD wiring, or my Trac/vsc system, or my multimode system.
Theres no way im gonna be the one to spend the dough and hack up my truck to find out..
In an 02, a direct ECU swap is not an option... You'd have to wire your neutral safety switch to trick your Automatic ECU into thinking you're in neutral, while your manual transmission does not require any input from the ECU to operate. You'd be able to retain all of your URD wiring.
If your ECU thinks that you're in constant neutral, there shouldn't be any reason for the engine to operate incorrectly. If you were to attempt driving your truck without messing with the ECU, you'll throw codes and possibly have some sort of acceleration issues as the ECU prepares the engine for an automatic shift.
There are definitely some people who've managed 5 speed swaps while retaining their Auto ECU's. I am not sure if you could retain your multimode transfer case, there wasn't an available option for the manual transmission. You could probably bolt the T-case up, but the transmission is designed for J-shifter T-case... I don't know enough about how the multimode shifter itself works. This is where Google comes in.
If you can't keep multimode, there's always a J-shifter T-case,. The glory in this setup is that your whole transmission and 4WD setup would be mechanical. There's nothing electrical that can prevent them from working. I initially wired my T-case to the ECU as per factory, though I removed those wires in the interest of keeping one less element away from the computers. Working flawlessly to this day.
I'm not an expert in the subject as I've swapped to a 5-speed ECU... just chiming in to help illuminate your options. Unfortunately, a 5 speed swap looks like a hellish long nightmare in an 02. I'd go with a valve body replacement in the long run...
Good luck, dude!