lots of options, nizpro, venom, ultrex, empire etc.
heaps of other crap out there that a just rebrands of other brands, looking at you ultrex. and un named brands from any exhaust shop.
end of the day get what your wallet wants and goals with the car, I had 4inch full xforce mild steel, after a few years it was all rusted, sh*t quality and sat too low. did sound good though.