"One we tested in Australia came back with 287bhp (211kW) and another, 294bhp (216kW).
"We don't communicate that officially, but if you remember in the early 1980s, a lot of manufacturers were [claiming something] like 160bhp, and the cars for the press were doing 160bhp, but when you take the car that was sold to the customer it was hardly doing 135bhp.
"With this car it is the opposite - we know of some customers who get 20bhp and maybe 30bhp more than what we officially declare - but we have to do that, because we don't want to declare too much power.
"We just want the customer to say 'My car is great, I love it'. We are comfortable with that."
Official power outputs for the upcoming RS265 are 196kW and 360Nm.
"The worst engine that will ever come from the Cleon factory will never be under the 265bhp (197kW) minimum we have announced officially," said Calcat.
Calcat said the RS265's performance upgrade will probably be the only real headline feature for fans in New Zealand.
He said the power hike was driven by the marketing team, which deemed it necessary against advancing rival hot hatches like the Ford Focus ST and Opel Astra GTC.
"To be honest, it is a very minor adjustment from a cosmwEtic point of view because the car really works," said Calcat.
"The major change is we have slightly more power. It is not that the car really needed more power, but it needed to play catch-up with its competitors.
"When you are in the hot hatch world, you always need to come with more - I don't know until when, but that is the idea.
"Our competitors like Opel with the Astra GTC now comes with 280bhp (208kW) and you never know when it will stop."
New Zealand-Australia is now officially the third-largest RS250 market in the world after France and Germany.
