THE STi uses a strengthened version of the WRX's turbocharged EJ20 2.0-litre boxer engine that features an Active Valve Control System (Subaru's version of variable valve timing), which electronically adjusts the intake valve timing through a range of 35 crankshaft degrees. The list of modified and strengthened components includes a semi-closed deck cylinder block, forged pistons, stronger conrods and big ends, revised camshaft timing and lift, hollow stem intake valve with sodium filed exhaust valves, variable valve timing, engine oil cooler, larger more efficient IHI turbocharger and a larger intercooler. Maximum power is 195kW at 6000rpm with peak torque of 343Nm arriving at 4000rpm, although in excess of 300Nm is available from 2800rpm and is maintained all the way to 6000rpm.