Several years back I ordered an original type replacement system for my `77 from IAP. To my surprise the muffler section was stamped "ANSA." Not the double outlet one that costs big bucks but one that appeared similar to the one that had been on the car since I bought it in `88. (I cannot say if it was original)
In any case it sounds GREAT. Gets compliments all the time.
Two years ago at a FIAT gathering I did a side by side comparison with a later model (cat equipped) that had the upscale two outlet Ansa system. We each in turn started our cars. I knew which I thought sounded better, but was a bit surprised when the owner of the other cars frankly expressed the same opinion.
And that was when idling. On the gas it sounds even better.
BTW, when I spoke to the folks at IAP they told me that the parts they had in stock (at that time) were made by two different manufacturers. Guess I lucked out.
Oh, and it "sounds Italian." I know that may not make sense to some, but Italian cars have a sound just as Brit cars, Japanese cars and American cars do. A glass pack may or may not sound "good" -- that is personal -- but it will not "sound Italian."
If you are not sure what I mean then go to some large sport car events and listen. Each IS distinct.
-don