Suspension upgrade Qs for '65 coupe

[DeltaMustang65]

Well, the rear suspension is all put together. All I have to do is detail the undercarriage and I'll be out of there.

1 quick question. If it's necessary to lower the rear to match the front, will I have to drill new holes or otherwise mess with the sway bar? Part of installing the bar was to jack the rear up by the differential so that the weight of the car is supported by the springs, then drill the holes in the frame going by the bar's position. Will a 1/4" change in ride height alter the spring and frame mounting point's position in relation to each other too much and give me any side effects? It seems like the bar's movement is limited since it's not a factory bar, but I could be wrong.

I should have some pics up as soon as I get around to detailing. BTW, what do you guys suggest for the rear undercarriage if it was previously daily-driven and kinda crappy?