Putting in a Cam is just a small part of larger Picture, on its own it is (IMO) next to useless but to state that is not conducive to sales, If the true cost of what you are about embark on is thrust in your face it is easy to walk away.
Timing and Fuel, of course have to be changed to take advantage of the Cam change, the lack of a Decompressor is another factor that has been raised along with the Battery capacity/ability.
The 3 cams being discussed here ( HMC 2 and Tec 1 ) are from different Factories, They are like Chalk and Cheese, HMC stage 2 has the edge at the moment.
HMC stage 1 and Tec claimed from memory 20% gain and many were disappointed because they " just fitted the Cam" and did not advance Timing or change the Fuel Map.
48% gain in HP and a 7 sec 0 to 100kph did not happen with just a DNA Filter a Free Flowing Exhaust