Newby 82 500 sel owner questions

[scooter81]

I am replacing my 90 735i bmw with an 82 500sel (greymarket car) it has 290000 km on the odo previous owner for 10 yrs was a fastidious professional mechanic. The Benz runs well and drives quite nicely and appears in super condition body and interior wise. My questions to you Mercedes litterati are ;
1 any trouble spots to look or look out for
2 is this an ok car in the world of Benz-dom
3 tough without seeing but a ballpark value I`ll confess later what I paid ~S~
4 anyone interested in a 215000 mile 90 735i with a questionable head gasket ?
Thanks in advance Scooter