I have a 2001 Boxster 2.7 litre and had the IMS Guardian installed. I am the 3rd owner and believe that the ims has not been replaced. Bought it with 30k miles, now has 40k miles. I bought this car with eyes wide open and did all the research on the internet. Fortunately at my stage of life if the engine explodes for whatever reason it is not the end of the world. 90% of my driving is around the city so if something goes wrong the indy shop is close at hand.
As an aside I can see the problem if a young person buys a cheap Boxster and is not aware of the problems that can occur. Do your research before you buy. Knowledge is $$$$$$.....