Hey, I was on Monty tonight, and everyone was out like usual and this guy with a 5.0 Mustang, badass suspension kills so many guys that have done stuff to their car. He has done other small stuff but not much to his Mustang and he told me that his car is all suspension thats why he gets people. True? Could an Eclipse technically be more efficient with good suspension kit? If so, know anywhere?

 

I bet he has an airbag suspension in the rear right. The Stangs have an issue with torque in that the body wraps up and drops all the weight and torque flex on the rear right wheel. In other words he has tightened it and solved his launch/roll issues. For a Stang, yes, this is important.
For any car, a stiffer suspension means more power transferred to the ground and not sucked up by the soft suspension.....imagine your car dipping the rear end when you launch or gun it during a slow roll. That dip just stole your power transfer.