*****Mine cost about $250 to replace. The Crossover pipe would normally have been a big hangup but I had recently replaced it with an aftermarket one and used new bolts, etc... I was amazed how quickly the mechanic did the job! Even happier to not have my garage floor full of oil spots from that stupid leak!!! All of my friends GN's leak oil. Knock on wood, mine seems to be leak free after the seal replacement. A big help was using the special PCV to seal out boost pressure better from the crank case. I have good valve cover gaskets as well. I'm not in R.I. but was happy to pay to fix the leak..