yea, ive heard both good and bad things about the hi-power exhaust. some say it rusts very quickly, others say that theirs hasnt rusted or anything in 2 yrs with no maintenance at all.
Rust occurs with the first generation HKS HiPower exhaust for the Celica. The one without silencer holes and the HKS engraving. Mine is the 2nd generation with the silencer holes and engraving and it won't rust. It'll only rust with the first generation so make sure, if you buy an HKS exhaust to try and get one with silencer holes and the HKS engraved right on the tip. (not all 1st generation rusts, but a majority does)