Is Twillfast top really similar to German OEM
 

Looking to replace top on my '99. One local installer recommended Twillfast saying it's close to appearance on Stock German cloth.

All the famous fabrics are made by the Haartz Cooperation: Haartz Corporation |

Twillfast is a brand of the Haartz Cooperation, as well as Sonnenland is. Haartz just bought these companies and brands.

Porsche in general uses the Sonnenland fabric for their cars.

Regards, Markus

Some good background on this site though I don't know where they got the "zipper" info:

https://www.convertibletopguys.com/convertible/790/1997-02-Porsche-Boxster

Some different info/ideas here:
Replacement Convertible Top Manufacturers - Opinions Wanted - 986 Boxster Top Issues and Solutions - RennTech.org Community

I use A5 GAHH.