Im having some big issues with my 98 wrx sti, i just had some work done on my car minor in a way, had my tappet cover gasket replaced due to oil leak which has been replace 4x now apparently they cant find the sorce of the leak even though there was a crack in the bottom of the origional cover which has been replaced, at the same time i had a set of tuned lenth headers(which will be for sale soon not my thing) put on with expansion flanges and fixed uppipe (no heat wrap due to lack of space) and had to be bent slightly because of the clearance between the headers and the tappet cover, at the same time i had a simese down pipe fitted and into a varex 3" muffler now i was pleasently surprised with the results until i took it for a drive to wanaka where it all has started to go bad, now my oil leak is back, there is a knocking coming from the engine (maybe big end bearing???) and when my turbo goes to hit boost there is a clicking as well as the turbo noise which is highly worrying and it also battles to get to 1.0bar which has never had the problem, i have not driven it since getting back to home i have turned it over and warmed it up to see if noise is still there and to my disappointment it is, after spending well over 2.5k on the oil leak and the minor exhaust upgrade i am left feeling confused and disapointed, has anyone had similar issues from these modifactions and can anyone recommened a good mechanic/specalist in the canterbury region as i dont want to take it back to the the same place only to feel un trusting of the work they do. the engine itself is well looked after and not abused and just clicked over the 100,000k mark ???