Hello! Seems these forms kind of do their own thing lol.
I'll try to help best I can, I have a 2.5RS of the same year so should be the same engine.
Just a starting point the engines are pretty noisy, freaked me out at first, but you quickly get an ear for what is normal and not.
1. I bought mine around the same time, timing belt is stupid easy on those/these cars, I know there are DIY guides floating around exactly how. SOHC NA engines though really are a breeze to work on. While you're in there I would replace all the other pulleys/waterpump/tensioner/might as well do thermostat too if you do water pump. should be roughly 500-600 in parts for all of it through a dealer. Can definitely source parts elsewhere for less.
2. Headgaskets leaking at some point. Mine happened at around the 140k mark, but mileage various greatly. If you have the time and money might try to knock it out all in one go. (belt/pulleys/etc)
If you want to wait or the headgaskets have already been done do the belt if it hasn't. These engines are interference so if timing is thrown off bad things will follow.
Far as my experience:
130k had to do front and rear O2 sensors because they were fubar.
140k Headgaskets started going did timing belt too
160k got a new passenger halfshaft
180k AC idle pulley seized and thermostat stopped opening (10mins to change out the pulley and maybe 20mins for the thermostat, my fault of neglect really)
190K balljoints were going and getting some old pulley sounds.
Did the balljoints, waterpump, belts, pulleys, tensioner (Pulleys and tensioner were going out)
Can't remember when, but I replaced the alternator at one point. This is all with oil changes every 3-3.5k etc. Don't forget the PVC valve either!
To be honest in total maybe spent slightly over 2k over normal stuff in the last 4 years keeping her going and hasn't ever stranded me or regretted it one bit.
3. B4 is the twin turbo version if memory serves, never came to the states.
4. Honestly not a whole lot with the NA motor, I mean you can do a better air filter/intake, exhaust bits. I did a grimspeed lightweight crank pulley and I can say you lob off a good 5lbs and the engine loves it.
Honestly the EJ251 doesn't make a ton of power, but it puts it down right with the AWD to get you going very well.
5. Don't really have a good answer for this, subaru makes some gauges, but man oh man are they an arm and a leg.
Oh one other note is that there are a lot of issues with P0420, it's an emission code commonly with the rear O2 sensor. If you ever do uel headers more than likely it will come up.
For these years it really only monitors the catalyst efficiency and in my case I replaced the sensors and cats with brand new oem parts to rule them out.
Still had it so I got a sparkplug anti fouler, drilled it out and used it as a spacer for the rear O2 sensor and have been good since. (18mm size if I remember correctly)
Hope that all helps!
Last edited by TheCr4zyM4n; 02-05-2014 at 02:13 AM..