Welcome. I see you want more power out of your ///M.
Where are you based?
If you in Guateng, power is hard to get out of the NA ///M engine due to our altitude. But, you could look at getting more aggressive cams. Shrick Cams are recommended as the best for NA M3's, but depending how aggressive you go, will need a retune. You can gain some serious power from just Cams, but you lose a lot of comfort as your car now pretty much idles like an old Amercian V8. Still damn cool.
Just doing software doesn't really get you massive power numbers. It will make the car have more response, maybe a few extra horses, but thats it...
You could try go for the CSL intake, but then you will need ALPHA N tune and that is not easy to get right. We've already had a member on this forum get his ECU locked by trying to install a CSL intake and tune his car for ALPHA N.
You could look at getting a Project Shift Airbox that has just recently entered its next level of development. You can see a video of this airbox on my M3 below. This was taken in Feb this year when I was testing the first prototype for Project Shift.
[video=youtube]
All the above mentioned mods will give you some good power. But dont expect to go racing GTR's or Ferarri's.
If you want to go into their territory, you will need to do either a supercharged conversion or Turbo.
My M3 is set up for Supercharged system while another member on this forum, BURGY, is fully turbo'd. If you are interested in going that route, feel free to PM either of us and we can advise.
None the less, beautiful car and welcome to this awesome forum mate. :thumbs: