I take your point, You can't argue with the fact the engine is giving out more power/torque so is under more stress though.
Fair point, but honestly speaking its not that much stress, espeacially on the TS's and V6's as they are Naturally Aspirated. But i've heard of a few JTD's etc mapped to the extreme with a lot of black smoke on acceleration and the turbo goes pop eventually on the new brera's, spiders and 159's you can block the particle filter.
A bad map can cause stress on the engine as there are some maps out there done by unprofessionals who just chuck a whole lot of fuel and modify the ignition timing, too much fuel = bore washing running too rich, melting pistons etc etc, can also happen if u run v6's to lean. Also you'll always keep tripping anti knock sensors, so it will retard the timing.
So its always good practice to go to a good mapper who knows what he/she is talking about and has a rolling road and equipment to measure the fueling when running the car on the Dyno.
Also my old 146 TI had like 140k when i sold it and was mapped at 65k miles, not a single problem. Suppose it depends on how you look after your engines - oil change every 6 months, warm up engine before driving hard, cambelt changed on time, right amount of coolant/water combination, good quality fuel, all sorts of things, list is endless!
I say Remap the car somewhere good, stick to a good maintenance schedule and enjoy!