I would work on the ignition timing first. Your off throttle was way conservative and I would consider moving the on power bins up 2* at a time and start finding the limit. Any idea if the detonation sensor is working? Time to find out.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.