Are these headers crap?
 

http://cgi.ebay.com/ebaymotors/Porsche-Boxster-986-97-98-99-2-5L-6-2-1-Exhaust-Header-_W0QQcmdZViewItemQQfitsZModelQ3aBoxsterQQhashZitem 2c5a1cc667QQitemZ190490396263QQptZMotorsQ5fCarQ5fT ruckQ5fPartsQ5fAccessories#ht_2421wt_1165

These would be put on a 2000 non-S (2.7L). Planning to pair a set of headers with OEM muffler. Would headers eliminate the need for bypass pipes?

Now I know they aren't gonna be $1,000+ headers, but has anyone had any luck with these "lower-priced" options available on ebay?

Similar to the 3.2. engine, the 2.7 variant also utilizes two sets of cats. First, there's what's referred to as the pre-cats which are incorporated into the headers . Next, there are secondary cats that are located downstream - just before the cat back exhaust. The secondary cats can easily be by-passed without any concerns relative to the vehicle's ecu . However, removing the header/pre-cat setup requires relocating O2 sensors and possibly re-programming the ecu in order to avoid cel's. Both of these approaches have been widely commented upon, along with some highly polarized views as to the effectiveness of either modification .

ahh i see. with the bypass pipes, i don't see how it could negatively effect anything. if anything, you're reducing weight. i won't argue that it will give performance gains, but weight reduction is a plus as well as better airflow.