uh... when i get exhaust done for my turbo project... i was gonna get a cat + flex pipe put in.. so... i was wondering if these are ok:

cat:
http://www.car-sound.com/02product/universal/mirror.asp
or do i need one that allows an o2 sensor?

for flex pipe, does it really matter if i get a cheap one or not?
and what length do i need?
i was looking @ vibrant... they have a standard flex pipe w/ inner braid liner or an FI series one w/ interlock liner
the lengths range from 4" to 10"
here they are:
http://vibrantperformance.com/catalog/inde...db3b514c2016f1d

now, for an intake filter... what size do i need since they come in all sorts of shapes and sizes?
i was looking @ the round/straight and round tapered:
http://www.knfilters.com/universal/universal.htm

This is all assuming Canadian Celicas have the exact same emissions setup and laws as US spec cars.
They may be different, so this may not all be 10% correct for your specific car...

Also, I take it you are doing a 5SFTE?

Your 2nd O2 sensor isn't directly in the cat.
It is after it, to measure how well the cat is converting the exhaust products.
You will need to get a bung welded to the exhaust pipe after the cat for it.

Personally, I would recommend a Catco HIGH FLOW cat. You pretty much aren't going to find a unused one for much less than $100 US... There are plenty of after market 3" cats, but a lot aren't high flow.
Also, you don't need one with an air tube. If the one you get comes with one, no worries. But it's not needed on your car.

For the flex pipe, I don't know what the ideal length would be.
The longer it is, the more flex it will have.
But the longer it is the more turbulence it will also create....

For the air filter, :shrug: