Why different Rear spring for Pass & Driver side

[jpikaart]

I was detailing some items on my vehicle and noticed that both rear springs where part number P4120863. The Driver side is oriented with the 'partial 'helper spring' pointing to the rear of the vehicle and the Passenger side has the 'helper' pointing forward.

Doing some research on this part number I notice that both of these parts are designated as a passenger side performance spring.

My question is would these springs cause a 45 MPH vibration I have?

Am I OK with this set up or do I need to change something?

 

[1968FormulaS340]

I doubt the vibration is from the springs.

 

[Keyser Soze]

Vibrations come from rotational force. I'd start with wheel balance.

 

[jdsduster]

no vibes from the spring itself.id look at wheels,u joints,pinion angle.driveline related if moving,motor related items if vibes in park

 

[jdsduster]

no vibes from the spring itself.id look at wheels,u joints,pinion angle.driveline related if moving,motor related items if vibes in park

well i quess it could be spring related if the bushings are toast or loose