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://celicahobby.com/ubbthrea...#Post1953363709Theres 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.