I used non porous weather stripping and it works great. One side is sticky, that gets wrapped around the "male" surfaces. It compresses nicely when you slide on the pipe and seems to seal very nicely. FYI .... Seems to work great. The weatherstripping compresses and expands, so even with some movement, I think it will continue to offer a better seal than any sort of electrical tape. Just my $.02!
Tim (apparently likes "3" cars)
E90 M3 -- Current ride
2004 GT3 -- Sold
1997 M3/4 -- Sold
1995 M3 -- Sold