stillen often rebadges their product at a HIGHER cost.
people often refer to stillen as STEALIN
When they dyno to show HP gains on their products, they ALWAYS over inflate the gains. This has been going on since like 96 maxima and still till this day.
I know for a g35, stillen's HFC are the same as KINTEX HFC. Their SC are great other then belt slipping issues but that seems common on other cars as well. Exhaust systems are decent as well.
They do have decent warranty least for the exhaust and supercharger.