Perspective I suppose. If you need street cruiser or drag racing tires, there is a decent selection in the US of 15" tires. If you need speed rated, high ply construction, or high grip, d.o.t. approved UHP 15" rubber, there is virtually no choice, IMO.
Yes, typically for drag racing you want a lot of sidewall to cushion the impact on the tread face that is produced by the high rpm of the green light launch. In contrast, in a handling application you typically want a more rigid sidewall to reduce deflection and improve slip angles. The two disciplines are not very compatible.
Original equipment providers are continuing to put ever increasing diameter wheels on vehicles, so the selection of tires for sizes popular 5-10, or 15 years ago is shrinking, never mind finding true ultra performance tires for rim from 30-40 years go. This is why so many are migration to 17, 18 or even 20 inch rims. I surmise that eventually some of these custom width, large diameter tires will also disappear unless you are using a size that was offered widely on OEM manufacturer's vehicles.
There may be any number of wheels in central Europe that could be made to fit. The classic mopar bolt pattern is 5 lug on 114.3mm spread. There are numerous cars that utilize this pattern such as Acura, Bentley, Honda, Nissan, Mitsubishi and others. The biggest challenge with be finding a width and offset that is compatible with the suspension components in your Mopar. Similarly, if you go with 15" wheels, you can find some vintage tire offerings from Dunlop and Avon that have a fair amount of distributors in Europe. Will it be easy, no, but certainly not impossible.
Of course, all of that is contingent upon your countrie's restrictions and requirements for vintage vehicles. I know that some EU countries will only allow original or originally optioned equipment to be on cars that are licensed as vintage.
