I just had a ‘89 300SE last summer. Only kept it a few months. Beautiful light ivory over palomino leather, euro lights and chrome wheels. A rather high 3200 rpm at 65mph, which by the way is the same as the 81-84 300SD. Insufficient leg room in the back for such a big car. Slow/sluggish take-offs, however, pulls like a freight train at speed. And yeah, the idle was terrible and I couldn’t figure it out. Lots of oil leaking too and tranny fluid as well. A/C was still r12 and was the coldest a/c I have ever experienced in any car. Froze me the hell out. But in the end, I told myself that if I was to get another w126, it would have a V8 and long body... and now I have a 560SEL.