Coming from my honda days when OBX was just getting started....
OBX copied quaife's ATB differential and priced it at about 1/3 of what Quaife did. A friend and I put one in his civic, and because they didn't make the diff properly the axle's wouldn't come back out next time we had to pull the trans. In the process my buddy lost an axle, and the transmission case. OBX refused to stand behind their "lifetime" warranty. They wouldn't fix his diff, or refund any of his losses. Never again will I spend my hard earned cash with such a terrible company. It's funny to see that now they are making Mustang stuff.
I know these are just headers and there is less to go wrong, but you've been warned. On honda tech we started referring to OBX as "Oh we Be junX"
Now that I've left honda days behind me and come over to the v8 side, I will surely be avoiding almost any company that was ever associated with aftermarket parts for import cars.
If I were you guys I would continue to support companies like Kooks, magnaflow, edelbrock, and other quality manufacturers.