As soon as they plug in the obd computer to the car and see its on obd1 they'll know something is up.
This. If you're going boost, do not expect to pass smog, unless you purchase a full kit from GReddy or something. Even then, you'd have to run stock diameter exhaust.
Speaking of, I somehow missed that you have a 2.5 downpipe. That negates my 3in exhaust comment, as users have stated, it will defeat the purpose. Keep 2.5 inch. That vibrant muffler is great. My buddy ran it with no cat and 2.5 on his turbo B16 Del Sol. It was quiet until he went WOT. Also, avoid a cutout. As Jeff stated, adjustments in backpressure instantaneously like that will mess up your tune bad.
I still don't see 250whp out of a single cam without internal work. I had a hard time getting 320whp out of my B18 Integra without using ARP head studs. I think the head started lifting at like 280hp, and the B18 is stronger than any single cam.