Okay the depth of my problems is unknown but to give you all a chance at helping me im going to give a history of this car.
I bought it in 2011 and I flew out to pick it up from the subaru dealer in Houston TX. I did the transaction jumped in the car and like a guy does I romped on it and boy did it run. I didn't realize that it had a lot of aftermarket stuff done to it. Cobb intake, perrin tmic, perrin dp, grimspeed up pipe, and aftermarket headers i never did figure out the brand. I was 18 and didn't know much about subaru mechanics and I thought this car needs a tune so I bought a cobb accessport from a member on here and a hks silent high-power exhaust. As soon as I installed that accessport it started running different and it seemed to go down hill from there. Idle was rough, It didn't have the power it once did and I realized right away that I probly replaced a protune on the car but that was lost from me not saving it properly.
I might mention that it was running a quarter in 12.4 at about 114 mph before the accesport. I realize that this seems fast and I'm telling this cause I don't know what else was done to the car other then what I said earlier it could be a totally built engine for all i know.
The time came when I got the head gaskets replaced do to issues. I got perrin fuel rails and a borla header sometimes during this all and i was still running a cobb ots map (please don't judge me for this i know better now)
Well I got married and sold the car in 2013 due to issues and lost track of it and I all of a sudden got the hankering to try to find it to repurchase it and thru vin searching I located it and bought it back as is about a week ago. Found out in 7 years it had been thru 4 owners and only 20k miles put on it.
It still has bad problems, it totally failed a leakdown test, misfires in multiple cylinders, won't idle, smokes and leaks oil,
This is all fine and is what I expected but know when the rubber meets the road I don't now where to start for a rebuild im looking for around 450 to 500 whp but obviously I can't drive it to the tuner with all these mods on a rebuilt engine, or i risk damaging it. Im enthused about learning to do a rebuild myself to safe some cash but is this to ambitious of me? Should I go for a rebuild or buy a short block? Do I have to upgrade my turbo for that much hp?
Please bear with my sorry punctuation typed this out on a phone and it sucks.