Can't really answer your questions although since I re-chassied Woodstock, I guess I have fitted one, although the mounting holes on the wheelarches were unchanged, and the holes in the chassis needed had handy drilling guides in the sill boards.
Does stiffen up the car at the back which will have a positive effect on the handling as well as the intended safety aspects. You'd not believe the difference if you just jack one rear wheel - with and without a rollover bar.
I suspect it will have little effect on the value, although only a dealer could answer for sure. Many are fitted by owners who have no intention to compete after all.
