Wolfgang,
The power capability of the alternator will do nothing to harm your electrical system. The alternator will only provide the number of amps requested by your car, even if it has the capacity to provide 70. Your car, in stock form, should do nothing to draw more than Chrysler engineered it for. The only way it would harm your system is if you have non-stock electrical components that draw more power, like high power radios, electric fuel pumps, etc. If that is the case, you will need to upgrade your wiring system to take the extra power.
A good rule of thumb, by the way, is that the bulkhead connectors are the weak point in the Chrysler electrical systems; those spade connectors can handle about 35 amps before you get into trouble.
Regards,
Hawk