Easy install, increases power/flow, better sound
Car: 2018 Subaru WRX/STi Exhaust Set-up: GrimmSpeed Limited-Catted Divorced Downpipe paired with Greddy RS Race (Single-exit, non-resonated) Other modifications: Cobb Cold Air Intake, GrimmSpeed Electronic Boost Controller, Crawford AOS V3, Yimi-sports Dyno-tuned Fitment: No doubt, this fits perfectly. I don't think there is any other way to describe perfect fitment. If you encounter any issues, then the installer is the problem. Performance: In comparison to driving with a stock STi downpipe, you can definitely feel a smoother airflow with the GS Limited-Catted Divorced (GSLCD) downpipe as the piping is significantly bigger in diameter and has less restriction due to eliminating 1 of the 2 catalytic converter in the stock setup. This set-up is also paired with a GS Electronic Boost Controller (EBCS) to prevent over-boosting (upon tune). Additionally, the "Divorced" setup will also prevent over-boosting which I really like so I can increase power in the car while somewhat maintaining reliability by not over-boosting. Sound: My setup is loud as it is with a stock downpipe, but adding an after-market downpipe usually gives an expectation of significantly increasing the volume. This is not the case with the GSLCD down pipe. The volume of the car noticeably increased, but not significantly which is what I truly love about this downpipe. There are two major differences that I noticed when I upgraded my down pipe: 1) Gives my car a "growling" sound when I hit about 4k rpm which I think is really loud, but cool. I mean.. what would you expect at 4k rpm? 2) Creates more turbo spool (whooshing sound) Overall, really great downpipe. From welding details to performance upgrade, GS Limited-Catted Divorced Downpipe is exactly the downpipe I was looking for and will recommend to my friends.