Sorry, I have been away for a few days. When I first drove the car after putting on the headers, I couldn't really notice much difference. When I took a log, you can see that there was really only a power increase above 6000 rpm, and that's why I didn't notice any real difference.
I then sent the log to Edward, who retuned the car and now you can see the results in v11c and it feels really good, it is a very worthwhile modification.
Just to clear this up, before the headers were added my car had 100 cpsi cats and the front section modified, the original middle section and hot dogs on the rear. It sounded okay with the original front section of the exhaust, but since the cats have been changed and now with the headers it sounds terrible. It's a real tinny sound, almost like an early 70's Fiat 1100 or 1300, if anyone can remember them.
So the middle and rear sections of the exhaust need to be changed so the car doesn't sound like a Fiat 1100. The bloke at the exhaust shop said if I do that he is certain there will be more power, but I don't expect much more. Anyway, I will find out when I get ahead with the $ a bit.