Quote Originally Posted by APTuning View Post
The thing to remember about these boxes is that they are not actually modifying anything, they are fooling sensors and although they do produce extra power and in some cases people do report better fuel consumption. They have been known to have adverse effects which can also be the case of a bad remap! At the end of the day people will always sell these but I personally would never use one, but the choice is of course yours. I can offer a tuning box which actually remaps the ECU! It store your original software and then has another 2 maps to choose from which are normally economy and performance versions. These work by plugging into the diagnostic port each time you want to change the map and they even have basic fault code scanner capabilities. They of course do come at a price of £350+£10p&p but are transferable to another car providing you reset the 1st car to standard and that your next car is on the ever growing application list.So all you would need to do is purchase new maps for your new car.
There was a thread that i got involved in where as a guy who sells the under the bonnet type tuning boxes (who is/was a member on here) said that there was nothing wrong with he's kind of tuning device. You can ask most tuners out there about these boxes and i'm fairly certain that most will tell you to steer clear. I know of a well known tuning company who do sell them though and I sold one to a customer who promptly returned it to me as he was not impressed and after experiencing he's peugeot with it on I was more than happy to give him a refund.
So maybe buy one from someone who will give you a refund if your not happy with the results and at the same time maybe try a remap out to see the difference. That way you can judge for yourself!
I am looking at a tuning box for my X5.. I had one on a works car for 3 years with no problems. I know someone who had a remap and he had to pay again after the car went in for a software update, so i personally will be steering clear of them.

As you say.. there are good and bad of everything. Tuning boxes and remaps included, and i'm sure even the good ones have problems from time to time... thats how it works!!! BMW's are excellent, but has no one ever had one breakdown? ... i think not!