HKS Exhaust System - High Power Spec L II - Carbon or Titanium Tips - GR86HKS High Power Spec L II Sports Exhaust System for GR86 HKS lightweight design has reduced the system weight to a level competitive with titanium exhausts. The equal length and low exhaust pressure design has an increased bore size on the main pipe to suit the new FA24 engine. GR86 Features: Increased pipe diameter to suit FA24 engine Main material is high quality stainless steel SUS304 65mm midpipe, 2 x 50. 8mm pipework at rear silencer 94mm