i don't know much about nissans, but i can give some general things to look at:
first thing is that i never trust a shop mechanic that i never dealt with completely.(he might be a meth addict)
so the first thing i would do would be to look at the ball joints, front end bushings and tie rod ends.
also you might want to check the frame out a bit to see if it is bent. that's hard to do. but usually you can tell by seeing some paint chipping away.
does it have independent rear suspension? if so did the alignment shop align the rear tires.
check on line for some kind of recall stuff on that car.
check the wheel bearings and spindles.
i doubt all of the rims are bent or have flat spots but check them any way.
hope it helps. good luck.
