There's the Celica obx header, you need to cut the header to down pipe flange and weld on the supplied one though. It's what I have and it's lasted 2 years so far, it's stainless tho haha.
As for everything else it'll be custom. If you can weld you can try to do it yourself, but I'd recommend taking it to an exhaust shop haha.
If you want more noise you can change the resonator to a vibrant ultraquiet, im in love with vibrants stuff. Cuts out all the header rasp too.
My personal setup is the obx header, and a 2.25in catback to a 2.5 inch dual tip muffler. Vibrant resonator and muffler. Sounds aggro but not stupidly loud.