exhaust help!!!!

[jdm4life]

i'm buying a electric cut out plate for my 2003 mazdaspeed protege and it has a stock exhaust but idk the size is it a 2.5 inch? please help and lmk!!!! thanks

 

[Silverspeed2015]

i believe the stock exhaust is 2.5 but i would wait for another opinion to be sure

 

[theEZV]

the catback section is 2.25.