p0420 w/ catted pd ? help/advise w/ 3 q's

car is 05lgt 5eat , has 97k on it , vf52 , dw740cc inj , perrin tmic , kb pickup , perrin lwcp , gfb reponz hybrid in 100% recirc , greddy up w/ egt , cobb ap on base 91 oct e-tune for those mods , stock airbox , stock catback (please no boost creep).

turbo blanket will go as soon as it gets here (thanx msprank) , motor is sound . i am in eastern pa .

just installed a perrin 2 pc , 2 catted dp & got cel/cruise flash , checked/cleared w/ ap , came back next day after some highwayish drive . cleared it again & have been reading all i can find here & on nasioc for the past 9 hrs.

i know i need a retune for this addition , spoke w/ the tuner about the fact that my stock cats might not be 100% & i might go dp , they were ok but here i am w/ this dp anyways .

Q#1 : ok i know i can just have the tuner "fix" it w/ the ap/tune but my question is will the car pass obdII ? i know the dash will not light up but will the code still be in the ecu making it "not ready" for obdII testing ?

i assume the code came up because of the difference in cat material , size , density & such , tight stock cat matrix vs looser high flow perrin stuff . i'm cool w/ that .

mpg has gone down from 35 to 33 but this is short term , less than 150 mi so i can not be hypercritical of this aspect yet . alignment is probably be off as well , killing mpg .

Q#2 : i am aware that some peeps use the spark plug antifouler thingies as a mechanical fix but i am under the impression that the lgt's use the second 02 sensor to adjust fuel trims so i don't think i want to do that as that 02 sensor will not be seeing the "real world" . is this correct , the fuel trim part?

Q#3 : how do i set up my ap beforehand w/ all the parameters i want to datalog so when i am in car i just press "log" instead of selecting all the items seperately in car while driving ?

thanx in advance

Yes you will still pass inspection.

Don't mess with the rear O2 sensor.

Dunno about the AP setup, I don't own one...