The Defender is absolutely fine in normal driving with the mild remap that it currently has.
The issue is that l find performance less effortless when towing the caravan and wanted to see if any improvements could be made.
This is after reading posts on forums like these, where people say their "Alive Stage 1 remapped Defender towed their caravan like it wasn't there"
Always be suspicious of rave reviews, I can tell when I have a full tank of derv by how the car handles.
I can pretty much guarantee any tune that makes power will also make smoke when off boost.