Rust only occurs with the first generation Celica HKS exhaust that doesn't have the HKS engraved into the tip. The newer ones, the one I have, has no rust problems. A bit of surface rust but that's because of the weather here and that winter driving doesn't help. Nonetheless, great exhaust, but I kind of want a change to Apexi. Still great nonetheless, very quiet, unless you remove the resonator like I have.https://www.celicahobby.com/ubbthrea...#Post1953363709
Theres the link to a clip I have of my HKS without the resonator. With the resonator, expect the sound to be almost stock.
Gains aren't bad, not the best compared to TRD
, TPR and obviously Kazuma. But it's up there with everything else like the Apexi and Greddy.