I’ve used Thule straps for 21 years
and as far as them vibrating, I give them a couple of twists on each side of the boat prior to fastening down don’t get any noise from them. VERY EARLY on I used cheap rachet type straps and on my first time out, due to vibration, one of them broke. That was the last time I used any type of racheting strap. Hubby thought because he used heavy duty ones to tie down his bulldozer, the lighter ones would work for the kayak. Nada!
Use what works for you, but for me, I’ll use 'Blue" on my Hullavator, which this ‘shortie’ loves.
FOAM
http://www.campmor.com/shop-brand/riverside-cartop.shtml
FOR BOW AND STERN look to the rope or strap running thru a cloth reinforced radiator hose…search that here and on the net.
intelligence is required of all paddlers
Cam buckle straps
Have known many paddlers who do great with rope.
I’m not one of them.get quality cam straps.not the wall mart or harbor freight ones.i like front and rear tie downs.a simple extra measure. NRS Yakima are good choices. no matter how good your straps work or how well things stay put. checking things when you stop for gas food ECT.is a good practice.inspecting and replacing when signs of wear show. is a good habit to.
some are
Most factory racks these days have removable crossbars to keep the aero profile clean and save a few drops of fuel. And they vary in how well the factory bars secure to the rack rails, and in strength. I’ve seen a few that upon sight I wouldn’t trust. But I drove a subaru for years, the side rails had 3 attachment points to the roof, the crossbars were stiff metal, and they attached so soundly that I couldn’t move them fore and aft. Late 90s and early '00 subarus have pretty stout racks.