What tires sizes are you running?
Stock or wider rears?
I ask cause on my research since you are thinking about stepping up to a 19/20 there are ALOT more wheel options with 10-10.5 rears.
And more options on rotoformed wheels.
A 19x10.5 5x112 will cost $768 apiece unless rear hubs are "fill in drill" to a 114.3 then just a 73 to 66 hub spacer (which you will probably need anyway)