gasket will make a difference mate think about it the gases are leaking there an not goin through the exhaust as they should an yes you should have springs on there as it does give some flexibility in the exhaust.
on a better note just been to subaru myself to get my oil filter an sump bung for my oil change thursday cant wait to be up an running again still got to be careful for 500 miles but can boot it a bit more once dropped the oil
also got some prices for the rubber scraper strips at the bottom of my window there about 65 pound each ouch