SUV rails or foam?

Whats the advantage of installing rails? How are they better than the foam blocks?

Not sure what you mean, but anything
that attaches boats firmly to the vehicle is better. I have used foam blocks in a pinch, but the amount of fuss and improvising needed to get the boat under complete control is a headache. With rails and crossbars, the result is much safer and loading is faster.

By rails do you mean cross bars?
Rails are useless on a vehicle as far as I am concerned.

Cross bars are necessary for properly securing your canoe using double looped cam lock buckle straps combined with gunnel brackets.

You can go cheap and dirty using foam blocks, where your canoe will move at high speeds and or in wind.

Or you can spend some bucks and be secure

Jack L

Third party crossbars
Though I really can’t tell if that is what you mean… usually can carry higher weight loads without everything tearing off the roof at highways speeds that factory side to side bars.