Car roof luggage carriers

Since I now have a car instead of my truck & van I am finding that space is a big issue.
I am thinking about getting one of those roof luggage box things for the top of my car to use for camping this year.

Does anyone have one for their passenger cars?

If so do you need a roof rack or can you just mount them right on your car?

Do they scratch the roof?

Are there certain brands that are better than others?

Or are different types better than others (like they have the solid box ones then the soft sided ones like a big duffel bag)?

Are they easy to install with just one person installing it? Cause I am single.

Thanks everyone!

Just bumping cause I would think that at least one of you's have to have some sort of topper for your vehicle.

RE: soft luggage packs.

You do not need a roof rack, but one helps.

Yes they can wear away the paint! you can put down a fleece blanket or old sheet on the roof to protect the paint.

A soft pack can be folded and put away if you have no place to put a hard 'clam shell' carrier.

The hard clam shell carriers can be locked and are more aerodynamic that a softie-but with a soft bag you can snug it down it you aren't using all the space in it!

And the cost is something you may want to look at....will it pay for itself after a few uses???

Yakima and Thule make 'systems' that are used to carry stuff on car roofs.

It's been awhile since I looked at their websites tho......Good LUck!