not necessary... any cars no matter injection or carb ... ECU or non-ECU..
installing a VS or grounding kit or both will improve the electrical current flow in the car. Old cars will see the improvements more obviously.
the performance of the car is related to the electrical flow.. but it will not make ur car fly lar... VS is to stabilize de voltage therefore giving ur car a constant voltage for smoother electrical operations. Grounding kits gives ur car a better connection between important electrical components such as alternator, battery, distributor, ECU, headlights... etc etc..
when those gadgets are installed.. ur car get a stabilized n reduced voltage drop Voltage and this will make de sparks plugs have better sparks plus more accurate voltage interpretation of de ECU for engine management stuff.. and therefore contribute a to some increase in performance...
another thing about grounding kits and VS.. some cars will experience smoother gear shifts... especially on auto tranny...
anybody want to buy VS(khguan DIY VS) or grounding kits(c-ground).. can PM me..