Not really if you got bald tires on the rear of a fwd if you are pushing too hard your dead. If the car starts to spin which is loss of back end grip you can't get it back in a fwd car.
Fine for pootling about in a @*!# box to and from work, but in a 1.5 tonne 300HP RWD car, its not something you want to consider
Mixing also isnt anywhere near as much an issue with FWD cars which predominantly understeer off the road before anything bad happens. Its also no real problem in the Zed when its dry, its when you hit damp of wet tarmac that the car handles weirdly with mixed tyres.