Turbo upgrade advice and stock turbo question
Hey guys just seeking a little help/advice.
I have a 2004 WRX with 86,000 miles. I bought the car over a year and a half ago with about 66,000 miles on it. I finally recently purchased and installed turboback (3' custom all the way from the DP to the tip which is a brand name tip, id have to look at it) - and it has 2 resonators. I also have a K&N cold air intake installed. Those are the only engine mods I have done. I also purchased a catless invidia uppipe, which I will be installing over the next week or 2.
I have noticed that my stock turbo seems to be at its end life. When i had the stock exhaust on, I would notice what they call the "dentist drill" sound around 4000-5500+ rpm full throttle. And I also notice some spiking, especially in 2nd gear it seems like it wont peak (13-14psi) until it is around 4000-5500 rpm. and in say a 3rd or 4th gear pull full throttle it will spike around 13-14 psi go back down to around 5-8 psi then spike back up until near redline. I am assuming this is an indication of the turbo in its latter days, Id only assume so with 86,000 miles on it... 66,000 of those not knowing how the car was driven. If that is the case, I am looking to upgrade the turbo.
I know it is possible to find a used STi turbo (i think the vf39 or vf43) for relatively cheap.
With my 04 wrx engine, would it be wise to upgrade to one of these turbos? What I am basically looking to do is replace the turbo with a slightly better one, pref. a used STi turbo... and max around 280-320hp with stage 2 maps, about 15-20psi. What else would I need along with an upgraded turbo, and could I keep this expense within the price range of 4-600$?
also what is the stock 04 wrx turbo, is it the vf22?
Appreciate the feedback.