buy them best thing you can do for your car. That goes for all our cars verts and hard top. Unibody cars flex and over the years due to metal fatigue they flex more. As to price personally they are cheap. if you brought your car to me to fabricate and tool up for it it would cost over 400.00 in my time and materials. They are a bargain and the fit is good and you will notice an imediate rigidity to you handeling as well.
My friend just had the body shop that is fixing his 69 sports roof put them on his car, the guy at the shop told him, with them on, if that car ever hits the wall, it's toast... I forget the reason, but I will ask him today.
I would imagine that the car would do better if driven into a wall with the subframe connectors than without. And the opposite for the driver since the cars structure won't absorbe the impact as much as without... Could be totaly wrong here(?) but that's what I think.
(why anyone would drive into a wall is beyond me... but anyway...)(just kidding again )
I made my own in the shop at home. I cut 1/4 thick C-channel steel, torched down to fit, and drilled for bolt in. I bolted it to the car, tacked it together, took it back off, and welded it solid, and ground it smooth and painted it and then bolted it back on. step 2 same as the first. This adds about 40 Lbs to the car...