Hi Robert,
I am a German living in the USA and drove on the Autobahn for many years.
I had a 95 Suburban and now have an 01 Yukon XL.
My 01 Yukon XL with the 6.0 liter engine does 160 km/h, but only an idiot would drive that fast. Not safe at all.
I would not go over 120 km/h, 105 km/h is better.
Top speed probably is 145 km/h.
It really is not a car.
Treat it like an old big delivery van or a small truck.
It really is not a very modern vehicle.
The newer engine version starts in the 1996 model.
It is a lot better than the older one.
My 1995 Suburban was not very powerful.
Remember, the weight is that of 2 cars.
Take care, Eggert Johnson