Yes, both systems can work together,
you may install typical "tee tee" system to once equipment e.g. Fuel pump, and another system like this RFID to Ignition Coil etc.
So both can work together, but you have to carry two remotes alongwith you all the time with car key.
Regarding installation charges, this RFID system does not need any professional installation, so any electrician (or you yourself if you have sufficient knowledge of Car electronics) can install it. So its installation charges are just as other normal security alarms.
(as im a car enthusiast, so usually i do DIYs with my cars, so dont know about what are the charges in market, usually i do these type of installations myself in my cars)