Actually, I don't think you'll throw a CEL by having your CAT removed. I've had mine off for almost 2yrs as well as many other DSMers I know w/stock ECUs and haven't got a CEL. Have you tried removing the CAT and seeing if a CEL illuminates yet?

I did and it through a cel after my 3" turbo back exhaust thats why i was wondering if those o2 simultors on ebay were any good

mine threw a cel also after my full exhuast upgrade. check out the vfaq site, theres a post on there how to trick the ecu into thinking the o2 is still there. i havent done it to mine. i just let the cel run.

http://dsmtuners.net/forums/showthread.php?t=203992

My car threw a code.

Just make it your own. I did & it was pretty easy, if you understand the concept of wiring in parallel/series. Read through that thread & it should answer all your questions. I did what Miden said, & wired three 50 Ohm 10W resistors in parallel, in place of the ~12 Ohm resistor the Vfaq page said. Wrap it all up in electrical tape really good. My car doesn't throw a code anymore.

Edit:Here's some pictures that shows the difference between series & parallel, in case you don't know...