Here is a bit of a plug for a product range that's hard to get here in Oz.
About 4 or 5 years ago my son & I got near drowned. He was coming home for a leave, & I went to pick him up at an airport about 75Km from home. The weather radar showed clear, so I took the 8, knowing he would be dying for a drive of something a bit fun.
45 minutes later it was pouring down, an inch in 30 minutes, & the water was running in, not dripping in, through the stitching of the back window, & almost everywhere else.
After I got there it rained so heavily the aircraft had to stack for an hour, it was too dangerous to try to land. When we finally got back to the car it was a swimming pool. The Mohair was totally soaked, & those seat diaphragms really hold the water.
303 was recommended by the local auto trimmer, & boy was it hard to find. It did give a slight shininess to the top, but that soon faded, & it was waterproof.
Fast forward to this week. The boy has left the navy & is coming home. He moved the 8, which has not seen rain in 4 or more years, out of the garage built into the house parking it outside, to load stuff into his ute in there. You guessed it, que the rain, 2 inches of it over night.
Expecting a disaster, he was so amazed he rang me to tell me. He reckoned just a few drips had got in around the back of the passengers window, & the thing was otherwise dry.
If any are looking for a hood waterproofing spray, I'd definitely recommend 303. Hard to find in Oz, but worth the effort.
Hasbeen