been doing dohc gaskets since, ooooh, around 92/93 so yes, i think i do know what i'm talking about
not that i'm saying the engines are crap or nothing, but if you snap the chains you take out no1 main bearing cap (been there, done that)
if you let the head gasket go then the head normally warps to the extent that you can't salvage them (been there, done that)
cams don't normally go, but tappets can be past it at 80k (been there, done that)
inlet manifold gaskets are another problem that needs solving (and you need new seals around the injectors because you can't get the buggers out and in without some difficulty (been there, done that)
the crank case breather that goes round the back of the head tends to corrode and give you no end of woes trying to figure it out (been there, done that)
and the never ending saga of weeping rocker cover and front cover and bottom cover gaskets is another problem that takes money rather than anything else to sort out (been there, done that, seen the film and even bought the T-Shirt)
not to mention the pourous rocker covers which crust up at any random age in their lives (working on an alloy one at the mo)

so yes, i think i know just a little bit about them

it's also cheaper to change an engine than it is to source a new head