I've recently installed my GrimmSpeed HiFlow Exhaust Manifold Crossover pipe and it's a definate improvement over the stock piece and compliments my ported OEM manifold setup very nicely. I didn't realize how the flex was constructed till I looked at it up close, well besides something in there rattleing you can see it necks down, ALOT. I was even able to put the heatshielding back on the Grimm pipe! So it's coated and shielded! I don't have any horsepower figures as my car is in serious need of a tune, but just driving around town feels much smoother on acceleration, just looking at the two pieces it's obvious it will flow more. The ceramic coating feels nice too I'm hoping to get the car tuned soon, I'm positive this piece will show improvements!

Thanks GrimmSpeed!!!



GrimmSpeed HiFlow Exhaust Manifold Crossover vs. OEM:




more info here:
GrimmSpeed :: Subaru Racing Parts