HKS Hiper and Clearance. Those two things dont go together. If clearance is going to be an issue, the HKS hiper will pose a problem. Although i still think its the best exhaust out there along with its Carbon TI counterpart, the end of canister hangs low and if lowered, you will need to find clever ways to go up steep driveways and bad speed bumps.
I have had my Hiper for well over a year and I have never had and clearance issues. One time I had 4 people in the car going about 65 and hit a deep bump and I scraped a little bit. I am now lowered and have not scraped once. My driveway at my house is inclined and I had not scraped there.