I read somewhere that for a pipe of a given size, increasing diameter by 40% will equal the airflow of two pipe of said size. So splitting into two 2.5" pipes from a single 3.5" will not be a restriction at all, unlike using two 2.25" pipes. Food for thought.Today I bought an Apexi NEO to tune the car!!!! :woot: so now i can wire it and put the interior together! I also Machined an adapter disc to line up and weld both the ford and lexus driveshafts! this thing is coming together well!! and plans for the exhaust is 3.5" from the turbine to about right before the rear end were it will split into two 2.25" pipes into N1 style Mufflers..