To be quite honest you're wasting your money, you will spend a good £1000 to maybe gain 10-15 bhp at the very most
I couldnt give a rats ass what the website says in all honesty, like its previously been said, that increase could be anywhere in the rev range, not at peak power
I had a K4m 1.6 16v megane and they're 110 bhp standard, I had a full exhaust, de-cat, custom induction (pipework etc) and matched inlets and I put it on the rollers, it made 110 bhp, I did later find out the actual induction bend had came off the throttle body so i imagine it will have lost a considerable ammount of power through this, may be 5 bhp if you're lucky
So maximum spend £1000, gained maybe 5-7 bhp in the process
Best mod to do is meant to be a 4-2-1 manifold, get good release of torque, and I imagine with a re-map you may see gains of 15-18 bhp, but in all honesty, after you've spend a good £1500 to gain the speed of a 1.6, you could've bought yourself a 172, or maybe try a 106 gti/saxo vts, cheap thrills
Best mod i did to my megane was strip it out, free power to weight