I needed a new header/collector for my '90 Reynard so after making a few calls I settled on using GP Headers, http://www.gpheaders.com/ in Barnesville, MN. Zach Griffin and his guys did a great job reproducing the old header that was on my car. Their craftsmanship was excellent. The old header had Stahl's name stamped on the flange so I am assuming it was made by them.
The new header bolted up and the tailpipe also fit the transaxle mount perfectly. I had them make up a 'two piece' tailpipe so I can sub a muffler when needed.