Hi offiman,

As I see it there are two ways to lift a Gen 3 without sacrificing flex:

1. Use coil spacers

2. Carry out a "sub-frame lift"

The latter is along the lines of what you were suggesting. Although the Gen 3 does not have a separate chassis, the front and rear suspension is attached to the body shell via very substantial sub-frames. It is possible to space these sub-frames away from the body shell by quite a long distance, because the bolts attaching the sub-frames to the body are quite long.

A sub-frame lift is analogous to a body lift for vehicles with separate chassis, but there are fewer complications in the case of the sub-frame lift, because the placement of the radiator relative to the engine and the gearbox relative to the body remains the same, for example.

There is a company in Japan called AGC (Auto Garage Champ) that markets a Gen 3 sub-frame lift kit that achieves 6" of lift! Here are some pictures: