Chassi set up

Janne, the factory GR-4s used even heavier rear swaybars, but they also had two outboard bar supports (4 total) mounted in the muffler cutouts of the body. They then ran the bundle-of-snakes exhausts out the A/C grille. Running a heavier-than-7/8" rear bar may cause the stock attach points on the center frame rails to begin flexing, so the effect of a stiffer bar is diluted. In years of autocross, I drove a Pantera that was rigged this way, and we ran a stock 7/8" front bar with a hollow 1.25" rear bar. Worked fine.
The single most effective thing for a racing Pantera seems to be completely seam-welding the entire body/chassis. This goes on top of the factory spot welds and stiffens the monococque far beyond what's possible with other techniques. It makes all your further handling efforts much more responsive. It also means you must completely strip the car, weld, then repaint- which with today's prices is why more guys don't do this.

Thanks for your information, to seemweld the body for rigity sounds like a good idea because it woiuld not be so notiseable. But since my cars body is in great shape I do not plane to dismantle the car. Plan is to try and stiffen the body up by adding crossbars on strategit places (have to save weight other places). With such heavy swaybar at the rear did you then have lower spring rate?
More inputs are most welcome.

Janne