There were two variations of the EJ25D sold in the US market. The engine was introduced in 1996 in the Legacy 2.5GT, LSi, and Legacy Outback. That version of the engine used HLA heads, was recommended to be run on 91 octane fuel, had lower power and torque ratings than the later '97-99 EJ25D, and was only offered with an automatic transmission. In 1997 a revised engine was introduced that used heads with shimmed bucket lifters (versus the HLAs), was designed to run on 87 octane fuel, and was available with either a manual or automatic transmission. Because of the DOHC valve architecture, the spark plugs are more difficult to service in comparison to SOHC variations. The DOHC engines are therefore installed with platinum spark plugs and an extended spark plug service life of . The EJ25D uses smaller rod journals due to the phase 1 EJ25 offset grind crankshaft design, compared to the EJ22 of the same year, and the engines which use a rod journal. As well, the EJ25D from the 1999 Outback is a one-year only factory hybrid, which uses the phase 2 case halves with an 8 bolt bell housing (as opposed to the 4 bolt bell housing used until 1998), uses a phase 2 crankshaft and rods with rod journals, but retains the same pistons as the 1997-1998 variant to maintain the same compression ratio. The 1996 EJ25D uses different pistons than what was used for 1997-1999, which will increase the compression ratio significantly if combined with 1997-1999 EJ25D heads.