i hear u loose a little low end torque with 2.5in’ but gain more high end. right now i can get 2.25in’ mandrel bent exhaust but i think greddy and thermal make 2g teg exhausts with 2.5in’ piping…isnt 2.5in’ a lil to big for a non-modified natrurally aspirated engine(stock b18a). im just looking for the best gains…
2.5 is kinda big for a n/a 4 banger… I could see that if you were running low boost… but… 2.25 should do you just fine. Unless that is, your pushing over 250 horses. Just my opinion
2-1/4"
i go with 2 1/4.