all birds sat a bit low in rear , looking like they point up in front....I lowered mine up front 1 inch (by cutting coil springs one full coil, the cheep way)....others have used lowering springs...

if it leans to one side in the back , it CAN be a bent subframe, sounds weird , but if its bent up some on right up front ,it pushes left rear down...and vice versa....you could fix the subframe or adjust front coil by inserting a spacer lifting opposing corner

both these are cheepie versions of 'how to', not the best way , but works.