Here is a comparison between the stock muffler and the ARK Design Road Spec. The Road Spec is a center inlet vs a side inlet and is smaller and much lighter. The polished 304 stainless is higher quality as well.
The ARK Design down and mid pipe have smooth mandrel bends with less radius compared to the crush bent stock parts. The tubing diameter is sightly larger and the material and workmanship are superior. We decided not to run the down pipe and use the stock part for our test.
The ARK Design exhaust uses quality stainless beaded hangers and fits perfectly in the stock locations. Installation is super easy.
Howard bolts up the mid pipe. It will bolt to the stock down pipe if you wanted to run its extra resonator like we did so the exhaust would compare more directly to other exhausts on the market. The ARK Design downpipe might have a tiny bit more flow but we don't think it would have any effect on power with a stock engine.
The ARK Design Road Spec exhaust is a thing of beauty and fits perfectly as well.
In testing the ARK Design Road Spec exhaust, we had a few surprises. With a 148 hp @ 6900 rpm and 118.3 lb ft of torque at 6100 rpm baseline, our BRZ mule is the most powerful stock FR-S/BRZ he have yet to to dyno on our stingy conservative Superflow dyno. The ARK Design Road Spec impressed us with 152.8 hp @ 7000 rpm and 121 lb ft of torque at 6100 rpm. This is a gain of nearly 5 whp and 3 lb/ft of torque over stock. This is a lot for a bolt on exhaust on the FR-S/BRZ. The Road Spec exhaust is pretty quiet, not that much louder than stock with a nice slightly deeper tone.