Do-It-Yourself Auto Repair: Sometimes Not A Fix

I had water fill up 1/2 of my headlight, so when I drove the "light danced" swaying back and forth while I drove for a couple months...finally the headlight burnt out and I had the shop replace the whole headlight assembly. When I got the car back and started it , I could hardly hear the engine, it was too quiet...very low idle..drove fine on freeway, but when I began to do stop and go city driving the car would have low idle and stall @ stopsigns...when I put it in reverse...took car back to shop...they said they will test drive it and diagnose it....@ the same time I had them change the oil and the spark plugs for this 2006 Subaru Forester,.. mechanic said @ one point...over the phone...the car runs fine....he was doing freeway driving....when i finally picked up car 5 days later , mechanic said I could replace idle sensor....This would cost $1000.00 with parts and labor...he said he cleaned out the original idle sensor...but who knows how long it will last....acouple of weeks....months or years......(also, check engine light was on after headlamp change and before tune up_) but not now....it was on before mechanic cleaned out idle sensor....I have been reading all the info about Subaru Foresters and their problems... I told mechanic...OK..let's put in the part for $1000.00....I don't want to stall again. It took him 2 weeks to order "idle sensor" so I decided to just wait till car breaks down and fix it then, because car seems to be running fine now...There was a $100.00 restocking fee for the "idle sensor" part that nobody had and took 2 weeks to order....Now I am noticing the driver's window doesn't go up as fast as it used to ....and maybe the airconditioner is not as strong as it used to be...and maybe the car idles very quietly...I just don't want it to stall.....I Paid $300 for oil change and spark plugs...I called around..one mechanic said...take Subaru to Subaru dealer and let him diagnose the car... I called the dealer and he wand $300 just to hook it up to computer and give me a electrical test to see if the car has electrical problems....what should I do? I see alll these recalls for Subaru ...should I get dealer to do the recalls and see if I can fix car that way? or do you think the car has a short with electric problems now? I read the subaru manual...and with headlight replacement you have to move part of the windshield washer unit when you replace headlights...I just had filled it before I took to shop...now it's empty... What's your advice...do I need a Subaru specialist or are the all phony....should I get dealer to do the recalls? Please advise me....do you know of any good subaru guys in bay area?