I personally don't believe that any difference between the Morel's and Aura's will be noticed. Therefore, I'd go with the cheaper ones
As long as you high pass the OEM rear speakers at ~100hz w/12 decibel slope I'd say stick with stock. That'll give you a bit more change for front components. There's tons of deals for front component sets if you know where to look. Give me a price range and I'll see what else I can find. But on the cheap, I'd stick with aura.
If he goes with the cheaper but equal SQ fronts and keeps the stock rears, do you think he will have enough left in his budget to add some tweeters in the back? That would balance the sound better wouldn't it?
97 GT white 4 door-SOLD
Cherry 2005 Impala LS- Front and Rear GMPP Strut Tower Braces