Twin Power
I have one fitted in my car.
As to the difference it made ,I was unable to tell a for it was fitted whilst it had been remapped but I guess it help to take it from 450bhp to 500 bhp a little.
However , having a bigger and better spark must help in burning the fuel/air mixtuer a little better thus giving slightly more power and more torque . As to going through sparkplugs more ,I guess it proabably would , but hey as long as we get more power ..
You know what they say ,' every little bit helps !' but I guess it would depend on the state of tune of one's car. eg. If you don't ,for arguments sake , have an induction kit ,it would be better/more cost effective to buy that instead of the twin power !
If you do get one consider getting the wiring loom also ,for it looks much tidier !
My 2p's worth .