I am just taking some experience from my past of FI cars. Of my GTI and trying to add it to M3 here so any suggestions if very welcomed.
I have notice on FI cars everything seems to be the double the gain on whatever you mod.
like a tuned file is always more gain, a intake is also more HP gain, and a exhaust is also more HP as well.
so when I had my GTI I added a plasma voltage increase. I could adjust the voltage of the spark going through my ignition coils. Now because it was adjustable I when from (i think stock) 12V to 16V and then after when to 17V on a daily bases. I must say after by adding this the car feels very responsive and also felt a lot more torque. One of the problem I ran into when added more voltage was my coils didn't last very long so what I did was changed to the RS4 coils. That cured it and everything was fine!
Now here is my question: How come this type of products don't seem to be popular on the FI M3s?
as from my experience if you bigger mods. you will always have bigger fuel applications and if you combustion is also better doesn't that mean more power of more effcient?