Hi UDO after reading your reply I reread my post and realized I was not clear on my question.what I want to know about specifically is how well do the heat risers work on these two exhaust. is one brand better at getting heat to the carburetor base then the other. I have downgraded from dual carbs to a single carb for ease of use. I am not new to the Volkswagen seen just found this website so they made me a newbie. Can't we just say I'm not from around here. Sorry for the vague question.
The ones on the Vintage Speed exhaust works plenty well enough to avoid freezing. As Udo mentioned, it has more restriction compared to the CSP exhaust = creates more heat. I had the Vintage Speed on a mild 1915ccm engine. Looks good but kills HP.
-BB-