Anyone got any useful info on it.

 

It's a good thing, especially if you have aftermarket stand alone engine management. It's not really needed though if your factory ECU still has authority over ignition timing.

The way the J&S works is by pulling timing at individual cylinders when it detects knock. It's very good at it, but the factory Subaru ECU can do the same thing provided it hasn't lost that capability after a reflash.

 

I want to run nitrous on my STi is the J&S going to be insurance or is it gong to be useless.

 

If you use a wet system that is properly calibrated, it should be fine. I expect that the factory ECU would be within its authority range if your kit adds fuel with the nitrous. However, with that being the case a J&S won't hurt anything. There really isn't a reason not to run it, other than the cost. The main argument I would pose against it is the fact it is nearly as expensive as a reflash, but without any of the power gain advantages.

 

Are you referring to the factory ECU on a WRX?

 

Any OBDII Subaru ECU can adjust timing.

 

Thanks John, excellent info sources. Manufacturer support is always appreciated in our tech forums. Please make yourself at home.