Head gasket issues really only affect D2's from 99-04 and some P38s in the same time period (although not as prolific).
Rover V8s prior to the D2 were known to be a 200K mile engine largely...
Although you might be right, this is not what I have hear. In fact I have had great running 89, 93 in the 195k range that ran better than my D1 at 108k. What I have heard is if they live through infant mortality and then you keep them cool and full of fluids, they will go forever.
I've hand Honda, Subaru and one D1 change head gasket in their life. Subaru had 2 H.G. changes.
IMO, head gasket, although a PITA is not the REAL issue with the D2. But this is just from my interest in purchasing one, talking to a pile of D2 owners and resorting to D1 for simplicity and reliability.
From my discussions... D2 suffer cylinder liner issues (cracks and slips) that can ruin head gaskets and if the liner really is the problem, you can eat through them.
I have deliberately avoided D2 for 2 reasons... Don't really like the initial models of 99 and 00 and late 01-04 are the ones with cylinder liner issues. Of course all of this is a crap shoot because I have known people to drive late model D2 with a nearly obvious slipped liner for years. Great do it yourself project would be to get an '04 D2 with ruined engine from slipped liner and dump a earlier low mileage P38 or D2 engine from 99 or 00. There are plenty of good used sources out there so a project like this really is not that hard and many are prepared to drop ship engines, transmissions and other large parts B2B.
Anyway YMMV and I am only talking from what I have heard on the D2 engines. The more I talked to people the more I strayed away, if only because I did not wish to do another engine swap.