I am considering purchasing aftermarket headers for my 1996 st 1.8 i am curious if they make a difference performance wise and if its worth it. Thanks

How many headers ?
Answer - only one. You would buy a header.

Not really a performance gain, maybe a 2-3 hp.
Makes the bay looks better and they do change the sound of the engine.
I wouldn't pay more than $60 for one.

From my experience the corolla header and b-pipe fit the head and not the rest of the exhaust. You would have to have it mated up, fyi.

He can have headers, just not at the same time.

I thought they made a fairly noticeable difference on my 7A. Maybe not in total power but in how they shifted the engine's torque up some and let it breath a little better at the upper end of the RPM range. The eBay header is patterned off a 20V 4A-GE exhaust manifold but with a little longer and a little fatter runners, same cylinder pairing and 4-2-1 design. It's 'tuned' for about 4000-5000 RPM, with the 7A running out of power at 6000 totally it does move power up a little high but with correct tuning (or if you're pre-96, just adding some timing) that shift is very advantageous since it doesn't really diminish lower range torque that much. As far as small 4 cylinders built on late 80's design go, the 7A is a pretty torquey engine. I didn't feel like I lost any of that but gained more power up top. Win win in my books, especially since at the time I think I paid about $70 with shipping. Don't spend more than about $100 on it though and watch that you get the correct oxygen sensor type. There's flange or thread in, they do make an adapter to bolt to the flange that lets you thread a sensor in though.

If you live in a state that does emissions you won't be able to change it as you'll lose the pre-cat. Though if all they do is a sniffer test you might be ok.

Depends which emissions spec he is, 96 could have or not have a pre-cat

Mine was a '95 Federal spec and had it, so I don't see which ones wouldn't.

Also some states only require one cat to be present. I'd say go for it. I put an obx eBay header and a weapon r intake on the wife's corolla
Also a 7a motor and you can definitely tell a noticeable difference. Whether or not a computer tells you get a difference if you can feel it its money well spent. Her car does 60 like it used to do 40.
Increase in hp, couldn't tell you, better driving car definitely

I have a header and downpipe for sale. they have been modified to fit each other. you just have to take your header and pipe off ant it bolts right up. search for my threads in the for sale section

Thanks for all the feed back guys!

should be able to get $30 or so for the precast catt from people who buy old factory catts

cool swap!