box of resistors to fool ecu to fuel more but a remap puts fuel in where its needed and not where its needed SIMPOLES
Nonsense! These days almost all of them contain a microprocessor (ie. computer) which can actually make an informed decision as to how much extra fuel to put in and when.
In its simplest terms a tuning box alters one parameter of the engine management and in a way that does not interfere with the original programming because it intercepts the signal coming from the fuel pressure sensor and uses the CAN-BUS rev signal (which is present in the same connection lead to the sensor) to 're-map' the fuelling by substituting its own signal.
A 're-map' (which should really be called a re-programming) wipes the original map data for several parameters inside the ECU and replaces them with another set. In one sense they are better in that more power can be achieved as more parameters can be adjusted, but their effect on the wear-and-tear of the car is identical.
Tuning boxes got themselves a bad reputation because a lot of sellers were offering the same basic program inside the same basic box claiming they suited any car, which would give 'all or nothing' power delivery or substitute an out-of range value and trigger 'limp' mode. The better sellers alter the programming for different engines to avoid this.
A bad remap is worse than a bad tuning box. What is a bad remap I hear you ask? About 50% of them as someone simply dumps a generic file into your ECU which is no better than a generic tuning box except that when you realise it is crap you can't just unplug it and you have to pay someone to restore the factory settings......
PS. One of the most prestigious BMW tuners in Germany (AC Schnitzer) fit tuning boxes....
PPS. I have owned and run several tuning boxes for tens of thousands of miles on several cars with no ill effects (apart from a premature clutch failure on one car - which would probably have happened with a remap).