Roadworksauto.com
Try Roadworksauto.com I purchased interior carpet from them for my 1986 Ferrari GTB (cut pile) and was very happy with the quality and price. They most likely have the patterns for your car but the best way to get a perfect fit is to send them paper patters of the OEM carpet in your car. They will cut it to fit your exact specifications. I noticed that they do carry red. Good luck. Tell Fred and Roadworksauto that Kevin from Austin, Texas referred you. Fred did a great job for me so I am returning the favor and passing along this recommendation to others.
ps: I am a new 1986 Alfa owner and I plan to redo the carpet in my Alfa too.