It is actually not that bad, since tax depends on displacement and pollution, insurance on horsepower and model specific risk:

Costs are in Euro, per year:

230 E (catalytic converter by Paul Wurm)
tax: 117, insurance: 280

Citroen (600 ccm engine):
tax: rougly 200, insurance: 107 (if you hit something, no damage to the other party ;-))

Suzuki:
tax: roughly 250, insurance roughly 200

Fintail (not registered right know, as you might imagine)
tax: 190, insurance: 80

The W 116 is the problem, since it ist not yet a vintage car.
To register it in Austria was roughly 140 Euro a month.

The car is not registered right know, we consider a solution in germany for cheaper costs.

Since two of us use the cars it is, in overall costs, o.k.

Kind regards
Eberhard