[Mark_T]

The earlier cars had an issue with D-chunk failures, not IMSB failures. They IMSB failures ramped up with the change to single row bearings. If I had a single row I would probably do the upgrade but, as I don't, it can wait till I do the clutch which isn't even close to needing replacement as this point.

The tips are more likely, not less likely to fail, for the exact reason stated - they aren't driven as hard. The trick to making these engines last is to keep the revs up and drive them like sports cars. Babying them is a recipe for failure.

Lifters frequently go bad. Ask Jake. And adding snake oil to the engine is not a fix. Replacement is a fix.

The tensioner paddles do wear. You can keep an eye on this, as Thom mentioned, by monitoring cam deviation with your Durametric. Also keep an eye out for bits of dark brown plastic in the filter when you change the oil.

I know you're getting conflicting advice here, but if you do some reading you'll find that jcb986's advice contradicts that of the people here that know what they are talking about on just about every point. You'll have to make up your own mind on who to believe, but you can't go too far wrong listening to people like JFP and Jake - guys that work on these cars for a living.