I've also heard bad stories about OBX, namely their turbo manifolds. But I've seen their (Honda) headers 1st hand and they are relatively well constructed.

EDIT: Besides that, as stated previously, I think there are only 2 off-the-shelf aftermarket headers for the 7M-GE. I would pick the OBX, hands down, no questions, and get it ceramic coated too.

headers would make a whole exhaust system flow better. im guessing about...15-25 hp from a whole good exhasut system. which is a lot (~10%) for the motor only being around 200 in the first place. but the car has a 17.5-1 power/weight ratio. so every 17 lbs you take off, you gain a HP. On my monte carlo i took a full 2nd off my 1/4 mile by taking out the back seat, carpet(floor is cheap rhino liner kinda stuff from home depot now), sound insulation and AC/heat box. it wouldnt be very smart to take all this stuff out of your daily driver, abut you can do other things like fiberglass hood/fenders and stuff like that if just want it to be faster, and maybe cheaper.