An oil leak at the spark plug area (spark plug tubes) can be caused by a failing valve cover sealing rubber and/or camshaft holder o-ring. The sealing rubber and o-ring will need to be replaced to address this issue.
Honda Civic Si Problem Reports
RepairPal Verified Honda Civic Si Problem Reports
Front compliance bushings may crack and break. Damaged bushing should be replaced before damaged is done to suspension components.
On certain models the engine RPM does not drop immediately and can cause a surge when driving in first gear. A software update is required for this repair.
On some models the bump stop in the strut can cause a noise on turns. Replacement of the bump stop will fix this problem.
On some models the drivers and or the front passenger door glass will come out of it's track. The door glass will have to be replaced to address this issue.
On some models with automatic transmissions, during a cold start at high altitude the brake pedal feels hard. Replacing the power brake booster and updating Powertrain Control Module (PCM) the with a Honda software update is needed for this issue.
On some engines a sticking variable valve timing valve can cause the Check Engine light (MIL) to illuminate. Replacing the valve and a software update will address this issue.