Yes, if you have a vac wiper system, dont use mine. There is no way the wipers would still work. I personally cant imagine ANY reduction whatsover in vac to the wipers being a good thing, but I have been wrong before. So I see the road draft tube solution you and Dave use is closer to the original setup. Interesting.
When I did this 13 years ago, I had no idea there even was a stock solution. I just did the math and installed the one that would work best if the vac wasnt used for anything else. Works great, but I can see why not for those with vac wipers. Thanks for the part numbers!