yes... u can use a Perfex KT-18 Transmitter with a 2.4GhZ Mini-Z but no, you do NOT have to pair it every time you go from dnano to mini-z. you'll probably have to modify the settings (probably just the trim) for use with whichever model you choose to run at the time.
when pairing a transmitter to a model, that pairing is permanent until the car is paired with a new transmitter. a perfex KT-18 transmitter (and any other 2.4GhZ transmitter) can be paired to any number of models with a corresponding 2.4GhZ receiver, you just wouldn't want to turn those cars on at the same time
