I'm a bit oldschool when it comes to engine tuning and in pre ECU days have resorted to boring out, head skimming, faster cams, lightening and balancing , 4 into 1 manifolds, rejetting carbs etc. All physical, expensive and time consuming, but logical.
Now we have the magic pill that is remapping. For a couple of hundred quid you can go from 75BHP to 100BHP, get a smoother delivery,and maintain the economy. As nothing physical is being altered, am I right in assuming that the only things being changed are air/fuel mixture and ignition timing? What's the downside. Is it emissions, because there surely has to be one otherwise manufacturers who I take it know a thing or two about engine mapping would have a simple method of offering you another version of the same car.