I'm sure that the chip 'works'. It's just question of what you want to trade for more horsepower. That engine will put out 260HP for X years, assuming good maintenance practices. That same engine will probably put out 300HP for X minus 30%-50% years.
There is no magic in chipping an engine - its just air/fuel/timing - but you will be taking that engine beyond the parameters it was designed for, and into the unknown. All of those Honda cars running around with the huge aftermarket exhaust pipes and obnoxious noise? They were chipped, turning what was probably a 200,000 mile engine into an oil-burning blue-smoking monster that MAY last 70,000 if you are lucky. There are dragsters that get 2000 HP out of a V8 engine that originally put out 220, but it only lasts for about 2000 feet and then it has to be rebuilt.