I think i've decided on getting the N1 but i was wondering if it came with a place to put the 02 meter? and if i get a DP with no cat will it throw a CEL? or would i be better off just getting a HF cat? i just really wanna know what the best exhaust setup is without having the CEL come one?

the catback alone won't give you a CEL, neither will the downpipe--not sure about the testpipe though, I have one sitting here in my room though

A high flow cat will still throw a CEL I think, not sure about that one though...most HFCats are just resonators I think, i'm pretty sure they do next to nothing for emissions

The catback has a place to put the 02 sensor in it.
Im not sure about the 2G but I know the Apexi 1G Downpipe replaces the stock dp AND the cat. so there isnt a place to put the High Flow cat on with it.
Im pretty sure with the 2G turbos you can wire a resistor on the o2 wiring harness so you wont get a CEL. I know you can with a 2gnt, I had one on mine. Search around here. I know theres like 9878534 posts about putting the reisitor on.

Don't even screw in the rear o2 if you have test pipe or high flow cat. Plug the bung and wire up the o2 sensor. :P

ok well my next question is if i put on a "test pipe" will i run rich? i'm stil on stock turbo, fuel and everything and my mods are in my sig

Fuel curve won't be affected by test pipe. The first o2 sensor is the one that reports rich/lean spots.
The REAR o2 sensor is for emissions ONLY and really does nothing but trigger a CE light if it thinks the cat isn't working correctly.

ok i see. i was searching for this on tuners and everyone was saying that you run really rich and at times causes backfiring. but they were also talking about wanting to remove there cat and not wanting to get bad gas mileage?

Tony is a smart dude :thumbsup