I have a standard 55 WRX.

is it worth getting a K&N filter for it- will i notice any benefit from it, if so what type? green or red?

or there any other filters that are better?

what kind of HP increase will i get?

 

Lots of choices for the WRX, 'Green' cotton filter is one of the most popular.. may add a few BHP, but I think you would be hard pressed to tell..

 

so just wait till it's due a change according to the service schedule + get one just before then?

http://www.knfilters.com/search/prod...x?Prod=33-2075
this is the red one, but couldn't find the green on k&n's site.

http://www.technicalservicesuk.co.uk...ent_prices.htm

^^ selling them for £38 inc VAT

 

Green filters are actually made by the company Green
Both filters are pretty good and only lightly oiled so should have no MAF issues unlike MY99/00 cars.

Difference will probably not be noticable but should help the engine breath a bit better and the filtration maybe better then standard.

Also look into STi panel filters, lots of people fit them tem to standard boxes as well

 

i thought K&N made red or green ones, LOL

unrelated question-> i'm still running in, but my oil temp never goes much above the 1/4 temp line (ie JUST inside the normal range)-> is that normal??

other cars i've had (never a new one before) have been pretty much bang on the middle line after they've warmed up

will this change after i have the 1000 mile service + proper oil put in?

 

I had the STI one before switching to Green, personally I'd just change to another filter when the OE one needs replacing.. & spend the £38 on fuel now, LOL..

 

Oil temp
Unless you,ve got gauges fitted then this is the water temp and sounds normal.
Oil temp usually runs at 90~110degrees C