Limited Modified rear suspension.

I am coming back racing after taking years off.  My last Modified was a three-link of the past. This new car has a four bar set up on the drivers side and a Z-link on the right side. It has the mounting brackets to be all 4 bar or all z-link. I used to run 800 lb front coils and now this car has 650 lb. coils on the front.  I need some advice what coils are needed on the back now that they are mounted on the trailing arms instead of on the rear-end.

As far as shocks go, I simply ordered the Bilstein Modified package from Speedway motors. I'm still trying to figure out the rear suspension, never mind the new shocks of today...LOL  The motor is limited 9.5-1 and I'd say it probably does not have anything over 350 hp. Any advice would be greatly appreciated.