I would suggest that you see for yourself, both the JWT S3 and S4 cams have a loping idle with the S3 being less severe. This is what I was told when I purchased mine from JWT. I can't say for sure. I have never met anyone with the S4 cam. From experience the lope has not been a concern. It only appears to occur when I'm at a traffic light. It use to happen alot but I was told to turn the little light blue screw nob located just above my valve cover to the left and that would lessen the loping idle, It worked. Oh! I believe the S4 cams are more expensive. Give Jim Wolf a call @ 1-619-442-0680 and he normally is available for questions.
The website hasn't been updated in eons and is only basically informative. Hope this helps.
:flash:
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paradyme
95'G20t/AUTO/BLK
STILLEN HEADER/INTAKE/JWT/ECU/S3 CAMS/P11 99 G20 RIMS/
VIPER SECURITY/w/ REMOTE START/ ALPINE AUDIO