Hi Svein,
according to what I know there was no special exhaust made by Supersprint for Alpina. If cars were equipped with a Supersprint exhaust by Alpina it should have been the standard Supersprint sport exhaust system formerly also available aftermarket. The so-to-say official Alpina sport exhaust for 02 was made by Zeuna-Stärker.
At the moment it looks as if the Supersprint headers and sedan mufflers are available new in stainless steel. Seem to me to look similar to what was sold in the 70s originally from the outside, but I don´t have any informations on the current technical specifications and the inside. Resonators and touring mufflers were also sold in the 70s but don´t seem to be available now.
If the Supersprint exhaust was delivered with your touring the reason might be that I´ve never heard of any Alpina/Zeuna-Stärker exhaust for tourings but only for sedans. Supposedly in the absence of an alternative and in order to not have to keep the stock exhaust system with a perfomance-enhanced engine Alpina used the existing Supersprint system for their touring conversions.
I do have scans of the german ABEs for both sedan and touring Supersprint exhausts (technical drawings included either). Can send those to you via email if you want to.
Best regards, Lars.