3.0 V6 166 modifications gone wrong. Please help

I bought my 166 (1999 model) around 11 months ago. The car was fine but before I took delivery I asked the Alfa dealer to install a quad exhaust system and airfilters. He arranged for a company in Sydney called Interspec to do it. Since then I have experience a drop in power.

I have taken back to alfa all year. The air flow meter has been replaced 3 times and seems to make a little bit of difference for a while and then goes back to having a huge lack of power.

I am in a position to directly compare the power with another one as my mother has a 166 2001 model of the same specs but has the normal factory equipment. My mothers car is a rocket compared to mine.

Alfa has run the diagnostics and there doesn't appear to be any problems.

Has anybody got any suggestions? Please?

Hi James.

I have read that air filter modifications on a V6 can have a bad effect on the air flow meter, wait for some more advice but I think changing the air intake back to standard and getting a new AFM might be the way to go

I think you might be right. But I am also afraid that the exhaust modification may have been done without properly considering the exhaust flows, and maybe there isn't enough back pressure. If that's the problem I've wasted a hell of a lot of money and I am probably going to spend a lot more getting it back to stock!