Why think about it (IMS fail) when for $1200 you can do something about it.
Seems to be that would be the first I would do after buying. Before even a tune up and not matter what was going on with the clutch as far as wear.

Slipped sleeve--right?
 

What was your build date? The time frame in question is 10/98--3/99 when the sleeved motors were built.
As others have said, a lawsuit pursuing a remedy 10 years after the car was built seems doomed to failure. Think about a used engine..

Exactly Dave, thank you! The IMS "sky is falling" worry makes about as much sense as obsessing about the possibilites of cancer.

look at this as an opportunity to upgrade.

If you like your car AND it is in great shape - be honest with yourself, it is not worth putting a new motor in a car that needs other repairs- Then sell your core to someone like Raby or junk yard or people that rebuild these things.

If you are not hung up on your car, Get a used motor (4000) from a yard like LA dismantalers or simular and drop in a new motor. Sell the car at that point to recover some money- be honest about the motor.

If you want to keep it, then Raby is the only one I have ever heard of that can put a new motor in and keep this type of thing from happening again. However be prepared to spend more on the motor than the car is worth. That is why you will keep it...It will be better than before and you will get years and years of fun out of it.

I have this same rattle not sure what it is come from under the back right side of the car , I am sure its next to the muffler.......

I believe they make a 5W-40 for Euro specs.

Here is a list of factory re-manufactured motors on SALE from EBS.

http://forums.pelicanparts.com/boxster-cayman-forum/550426-boxster-996-997-engine-sale.html

Thanks ! I had ordered the 10w40 from Racer Parts Wholesale last night and managed to catch the order and change it to the 5w40 this morning.