Perhaps It's just a variation in the laws from state to state, but BBK's website (like many others) state that only non-catalytic midpipes are for "off road use" only. A long tube setup with a catalytic midpipe is completely legal in ALL 50 states. Only the non-catalytic midpipes are illegal in most states. Perhaps you should check with the local DMV or a local inspection station to make absolutely certain. It doesn't make any sense that you can't put on long tubes with a catted H-pipe. If the law really does forbid you to add long tubes in Mass, you need to be writing John Kerry a letter.
They might be legal to have in your possession in all 50 states, but a quick visual is all it would take in CA to get a fine. The factory midpipe uses 4 cats (or 6 depending on year) and since the aftermarket pipes only have 2, they won't pass a visual. Its also technically illegal to replace a cat before 50k miles (IIRC) if it is in working order.
I have the JBAs and mine cracked. It was a PITA to fix because they had to come off the car. You don't want to have go pay to have them installed and then pay to have them removed and then reinstalled again. Mine cracked at the #8 cylinder pipe, where it met the collector. Kind of a different spot than most people have trouble with. It pretty much cracked all the way around the pipe. The shop ended up welding a lot of gusseting on to make it stronger.
Having said that, the performance of these headers is very good. Almost LT good. I can't say what I gained with them because I installed them with a bunch of other things together. Bob Cosby used to run these in his FS '99 Cobra. He did a comparison dyno with them against a set of LTs and found minimal gains in the LTs.
The other benefit is the legality of them. They have a CARB # stamped on them. The retain the stock EGR equipment and since you can use the stock mid pipe, the o2 sensors stay in the same position. This is why LTs will not pass a visual inspection, in California at least.
The cracking issue left a bad taste in my mouth. If I had to do it again I probably would try a different brand of shorty.
Mine actually cracked at the flange between the number 2 and 3 cylinder on the passenger's side. I developed a nasty exhaust leak, and had to put the stock log manifolds back on the car. But hey, since then I've upgraded to turbo headers. So it's all good now.