I have this video in my sig but I'll put it here since I will change my sig sometime...
that is a stock L26 with a mystery header, 2.5 exhaust, roundtop SUs, and 2 individual air filters. The muffler is a generic turbo muffler. I also installed a basic MSD module.
The SUs are not tuned at all...
EDIT...
I LOVE the sound of my L26 but that is not really feasable to go with a L6 anymore...V8 or I4 it will bee...Leaning toward LSx since you guys are such a bad influence...