DOHC four valves per cylinder fuel feed by Sequential Multipoint Fuel Injection (SMPFI) turbo.
Originally designed for the North American Impreza STI in 2004 with AVCS and DBW.
2004-2006 STI model used the same shortblock, b25 heads, and valvetrain as EJ255 in MY 2005-2006 Legacy GT and the same block as the 2004-2005 Forester XT.
Later years used a revised block, piston and heads.
Notably, Dual-AVCS w25 heads appeared in 2008 STI.
The engine has a redline of 6700 rpm.

Usage:
US Market Impreza WRX STi MY 2004~2007 300 bhp (304 PS; 224 kW) at 6000 rpm (New SAE standard) and 407 N⋅m (300 lb⋅ft) at 4000 rpm of torque.

US Market Impreza WRX STI MY 2008~2018 305 bhp (309 PS; 227 kW) at 6000 rpm (New SAE standard) and 393 N⋅m (290 lb⋅ft) at 4000 rpm of torque.

US Market WRX STI MY MY 2019–current 310 hp (314 PS; 231 kW) at 6000 rpm (New SAE standard) and 290 lb⋅ft (393 N⋅m) at 4000-5200 rpm of torque.

US Market STI S209 MY 2019 341 hp (346 PS; 254 kW) at 6,400 rpm and 330 lb⋅ft (450 N⋅m) at 3,600 rpm of torque.

US Market Legacy GT/Outback XT  MY05~06 250 bhp (253 PS; 186 kW) (New SAE standard)
US Market Forester XT MY04-05 210 bhp (213 PS; 157 kW)
Asian, European Market Impreza WRX STi 05~present 280 PS (206 kW; 276 hp), 40 kg⋅m (392 N⋅m; 289 lbf⋅ft)
DOHC four valves per cylinder fuel feed by Sequential Multipoint Fuel Injection (SMPFI) turbo. Originally designed for the North American Impreza STI in 2004 with AVCS and DBW. 2004-2006 STI model used the same shortblock, b25 heads, and valvetrain as EJ255 in MY 2005-2006 Legacy GT and the same block as the 2004-2005 Forester XT. Later years used a revised block, piston and heads. Notably, Dual-AVCS w25 heads appeared in 2008 STI. The engine has a redline of 6700 rpm.
Usage:
US Market Impreza WRX STi MY 2004~2007 300 bhp (304 PS; 224 kW) at 6000 rpm (New SAE standard) and 407 N⋅m (300 lb⋅ft) at 4000 rpm of torque.
US Market Impreza WRX STI MY 2008~2018 305 bhp (309 PS; 227 kW) at 6000 rpm (New SAE standard) and 393 N⋅m (290 lb⋅ft) at 4000 rpm of torque.
US Market WRX STI MY MY 2019–current 310 hp (314 PS; 231 kW) at 6000 rpm (New SAE standard) and 290 lb⋅ft (393 N⋅m) at 4000-5200 rpm of torque.
US Market STI S209 MY 2019 341 hp (346 PS; 254 kW) at 6,400 rpm and 330 lb⋅ft (450 N⋅m) at 3,600 rpm of torque.
US Market Legacy GT/Outback XT  MY05~06 250 bhp (253 PS; 186 kW) (New SAE standard)
US Market Forester XT MY04-05 210 bhp (213 PS; 157 kW)
Asian, European Market Impreza WRX STi 05~present 280 PS (206 kW; 276 hp), 40 kg⋅m (392 N⋅m; 289 lbf⋅ft)
Subaru EJ engine