The Qa1 frame looks to be much stronger at the control arm load point and a large flat at the rear most frame bolt points where the wheel load is transferred to body.Also the tubing appears as thick as a well made class 3 hitch.By comparison the stock frame is a thin stamping with poor control arm pin retention area unless re welded with gussets.Ditto for the steering box mount. The vertical front tube , frame bolt design looks to me as similar to adding a front radiator brace , greatly stiffening the front uni-body twist.A mod to stiffen the front uni-body such as 14 or 12 gauge steel ,Rosette welded to the entire run of the front frame rails , before mounting K frame would greatly stiffen front end of car.