So I have the car running, good at that, but I completely looked over changing out the dipstick and dipstick assy to an STi one...how hard is this to do after the fact? What's involved in swapping it out? I know the WRX Dipstick is only off by a little, but it seems inconsistant.

Thanks in Advance!

All depends on which oil pan you are using. If you are still using the WRX oil pan then you should use a WRX dipstick.

If you swapped to the STI oil pan then you have to use the STI dipstick.

The dipstick tubes are the same, the only difference is the length of the dipstick itself. All you need to change is the actual dipstick

So you have the STI oilpan....i assume.

Yup, I have the STi oil pan...if the tubes are the same then hell, I'm a go to the dealer and get a dip stick!

Yep, it's that easy. I did the same on my build. It's always the small things you forget.

Sweet! THe dealer's parts dept is closed...looks like i'm gonna try on monday then :/ I've been getting all the little things i forgot and lost lately

the wrx and sti dipstick tubes are also slightly different in length, and afaik it will affect the readings on the dipstick. its a fairly straightforward swap but its easier said than done. its tough to maneuver the old one out, and its even more difficult to wiggle the new one in. pay attention to how the old one comes out so you know how to route the new one.

Is it as easy as unbolting, getting out and then putting the new one in the same "tube" that goes into the oil pan and bolting it in?

in theory, absolutely. however its like a puzzle to get it to fit in there. different angles, twists, etc are going to be tried until you can finally get it in.

some things to know: you can reuse the o-rings from the wrx tube, maybe. you may want to just order new ones to be safe.
the old one will 'pop' out and the new one will 'pop' in. this frees those o-rings from the oil pan, and they can be very tight. i was nervous from how hard i actually had to pull on the oil pan to get the tube out, but thats what ya gotta do.
other than that just be patient and you'll get it out/in eventually.