ok, i finally hit the 3300 mark on the OD. and i have ran the Bosch +4's in my other car i had, i loved em, so i wanted to see if they had any effect with the subie. so i went to checkers, asked if they had any, they looked up on the computer, all the computer showed for the new 06+ 2.5's where the OE crap but dont be sad! thanks to subie using the same 2.5L engine over the years, we cross refferenced the plugs with a 03 2.5RS! they had those instocked, so i bought them, hoping they would fit. they did fit! install time took me roughly 30mins. i would have been done sooner if it wasnt for the space limitations on the driver side, it'll take some time to get those out! the passenger side was a breeze, thats also cause i didnt have the stock air box in the way. the spark plug boots snap on & off, it takes some FORCE to get them off and on! make sure when reinstalling them that you push really head, you'll feel it "click" a little. after install, i fired her up. there was a difference. she idled smoother. so i took her for a test drive. WOW, what a difference on the low end power/torq [not much but you can tell there is a difference] also the exhaust note changed a little as with the intake sound

here are some pictures i took.





Bosch Part Number for the +4 Plugs (4pack) is 4417 (when they look up that part number, it will show them for a 02/03 2.5RS) total cost with tax cost me $30.00

 

I like the pics and all that jazz but, the Bosch +4 have not netted favorable results in Boxer engines. The combustion chamber design relies on a specific spark location. The +4 are pretty much hype anyways. The arch is only going to travel to the nearest ground. All the way to thousands on an inch. If one is even remotely closer that where it is going to travel each and every time.

 

oh well. i can tell the difference.

 

I'm sure you can

 

well there is a difference in the feel of my NA 2.5i, where as you might not have felt/notice anything in your WRX!

 

have fun with the misfire codes, platnum +4s dont do anything but make you get CELs i see them almost every day (working at a subaru dealer) the only performance increase from a spark plug would be NGK coppers, because they conduct electricity better. subarus HATE anything but NGKs

 

been in my car for over a week now, i have YET to see any CEL's!!!