Chris, I know about that car, and the change in the settings, Two of my best mates who went to the RR session with him where at my house today. lets just say you only have half the info :-)
I would disagree re my ECU, The technology for the first gen GTE was out dated by the time the 205 came along, for example no AFM on the later car. The stock ECU just over fuels to hell, safe to a point, but also increasing wear in the engine though bore wash . Toyota themselves had to retro modify the cooling system expansion tank after launch, so they do not always get it 100% right even with their millions. What about the stock manifold?, it has an design flaw that leads to cracking, unless you re weld, a better option is replacing it with a different one.
The mapping can be as safe or as good as the mapper, just as a stock part fitted to a stock car can be compromised by poor fitting by a mechanic. New technology enables one to achieve more, but if it is fitted by an idiot the results will still be bad.
Any modification done badly and without research can damage a car, that's a given. but people should not be put off by that, as sure as eggs is eggs if you neglect a stock car you can kill it just as quick.
plus in some cases, Toyota will no longer make or stock the correct OEM parts for older cars, therefore forcing you at times to consider taking other action.