If I already have a J&S Safeguard and a wideband O2 on my car, is it necessary to run the knock amp and O2 system that comes with the VPro or can I use the Safeguard and O2 in conjunction with the Vpro and avoid spending the extra cash on the HKS goods? Thanks in advance.

 

The J&S will not interface with the V-Pro. You should be able to get a pretty good price on the J&S used. The O2 will not work either. The A/F Knock amp from HKS is much higher quality then most other units on the market (excluding FJO and a few others) mostly becasue it uses the much nicer NTK O2 sensor.