M119 V8s need new timing chain and tensioner every 100k miles, it costs a lot, be sure to check the service record for timing chain replacement, other than that, most of other things can be taken care of by DIYers.
At that mileage, your probably need new belt, new belt tensioner, power steering pump may leak, it can be rebuilt. engine camshaft seals may leak, motor mounts may collapse, and needs new shocks of course. Also be sure to check sunroof and A/C, idle rpm should be paid special attention to, I heard too many M119 V8s had this problem, my 400E idles roughly when it's very cold, it's very difficult to diagnostic.
My 400E has 210k km, I went through most of the problems I listed above. , most of them are DIYable except the timing chain.
It's a powerful highway cruiser, not a street fighter.
99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.