I would stay away from the tie downs that only have the hook style ends and not the snap-hook style.
I was transferring a race car a couple years back and got all the way to San Diego from LA. Within a mile of the shop I was dropping it off at and after crossing a RR track I looked in the rear view mirror and saw the car trying to exit the trailer. Slammed on the brakes and kept it on the trailer. WOW. A $15 tie down is for a $15 car in my opinion.
Got home bought 4 new tie downs with the snap-hooks and gave them to the car owner!!!
Money well spent.
Try either of these companies. I just used Macs and got one of their pro-pack kits - great to deal with and a decent price for a quality product.
MACS Custom Tie Down
http://www.macscustomtiedowns.com/MR Products
http://www.mrproducts.com/