I bought my roll bar from Kirk Racing. AP and Kirk are similar in quality(with a majority of opinions leaning towards Kirk by a nose) but depending on what part of the country you could save a bunch on shipping . EDIT: I see you are in Sc, I would really check them out.>>
http://www.kirkracing.com
Whether its a bolt in or a weld in, both are going to stiffen the chassis signifigantly. Anyone says they dont is just plain wrong. It going to add some weight, about 70lbs or so, but the advantages of the added safety and stiffness is worth so much more than that.