The point is doing IMSB retrofit may give the owner a false sense of security that the engine will then become bullet proof. You may have equal probability to have your stock IMSB failed, or your timing chain snapped, or the IMS tensioner paddle crapped out, or your cylinders scored, etc. all require a rebuild so by eliminating only the IMS failure, you're still exposed to others.

IMSB is so popular mainly because it happens to be something you can retrofit without taking the engine apart. Now use engine prices start to come down and more economical to rebuild, it's not entirely clear whether one should spend $2.5k to address one of the weaknesses or just roll the dice and save that toward a used engine/rebuild IF the engine fails.

 

I bought a garage queen as well, took it to a Porsche dealer for full inspection, preventive maintenance, I changed all fluids, serpentine belt, spark plugs, tires, variocam actuators, later my Steering Lock Assembly Ignition Switch die so I had to get a new one and lately the roof is acting up (still waiting for my nerves to cool down and fix it).

I ask them regarding the IMS they said, enjoy the car and don't worry, they way I see it, If I get 3 years without the engine getting destroy, I'll take it as the same amount I'll spent if a lease a new 911.

 

Well and there was a high failure rate for a while that, in some cases, happened early in the engines life. Sure there are other things that can happen, but they seem to be a bit more rare.

Although, hop online, and people make it seem like any car north of the mason dixon line will have scoring or will get scoring soon and need a overhaul shortly after...