I dont have a picture for an aftermarket one(anybody know if they make a kit?) but find a picture of a GNX or Kirbans GNX kit and you will see the factory(ASC) installed bar. You will have to go with duals because of the lack of room with the crossflow muffler.
I should add that with these cars, the instant center doesn't come naturally. You have to alter the stock mounting points. Read Kevin Slaby's page. His nick is KEVINS. Do a search; it's very informative.
Instant center deals with weight transfer and the squatting behavior of the rear of the car when torque is applied to the rear axle. Instant center is determined by the mounting locations and angles of the rear trailing arms.
A panhard rod controls lateral movement of the rear axle and has nothing to do with the instant center.