Motorcycle Repair: exhausts-electronics., long hope, correct fuel

Question
I have a 2004 softail Heritage and I want to change my standard exhausts because I want a nicer sound.
Today I went to a dealer, I tought just to buy exhausts(or slip on's), but he explaned me that I have to put an electronic device,
or make an adjustment to the electronics. Either way it will cost me between 300 and 2.000 Euro.
According to him if I just replace the exhausts and no adjustment to the software the engine would not last long?.

Hope to hear from you guys if this is correct or the dealer just want's to earn some easy money.

Answer
What happens is when you change pipes to a more free flowing pipe, you lean the bike somewhat. you need to remapp the ECM so that the bike will get the correct fuel. The leaner the bike runs the hotter it runs, plus you dont get the horsepower you do when it running correct
Good luck and happy riding
Mike