Export Braces & Monte Carlo Bars

I've got a couple of questions on export braces and Monte Carlo bars. First, what is the differnece between an export brace and the brace I already have on my car from the cowl to the shock towers? Second does the addition of these part make a significant difference in handling performance. Of course the catalogs say they do, but they're trying to sell them.

the export brace is one piece compared to two pieces which means stiffer. They are also thicker. For what they cost they are worth it. Monte carlo bar goes from shock tower to shock tower and keeps the front suspension from getting "out of whack". I had both on my 66 before we put a coil over front suspension on and felt a big difference. No need for it now though.