Long time reader, first time poster! :-)
Alright guys... I know this question has been asked a hundred times by now, but I cant find another persons set up identical to mine, and running lean has me a little worried. Its kind of tame in comparison.
I had to replace my stock exhaust cuz it rotted out (why not go performance.. in that direction at least). I have a Tanabe Medallion cat back installed, OEM cat, and just received my Megan Racing shorty header today in the mail... the stock manifold is cracked.
No CAI. I still have the stock intake installed. I do plan on getting one eventually.. sometime down the road.
Granted the air coming in isn't as efficient as the exhaust leaving now. Having an OEM cat makes me think there wont be much of a difference atm. Tanabe is a bit more tame than others out there it seems.
Will these cause me to run slightly lean(?).

I am aware of KPro and/or getting my ECU flashed, but I'd like to wait until more work will be done.
Im somewhat a noob to RSXs... go easy on me please haha. Im learning more and more everyday though! It's the best I can do...
I planned on keeping it stock for a good while, but the "moding itch" has been hitting me lately. I wasn't planning on buying an OEM exhaust if the whole thing needed to be replaced anyways.

And sorry for this question asked again but I cant find a post with this setup- No CAI/Megan Shorty/OEM cat/Tanabe CB.
Thanks for any answers in advance. I could really use some advice, info, or opinions.