Do yourself a favor and do not use the 4 bar. I have had at least a dozen fail. For 20 psi, the factory sensor is fine. If over 25 psi, you can use the AEM 3.5 bar brass for gasoline or Stainless for Gasoline and E85 use. Never had the AEM fail. What is scary is that if you are using SD with the 4 bar and it does fail, it tends to lock up in one spot. The car may run ok at idle and cruise but then never get fuel on boost.
On the 16 Bit ECU, They will cause an oscillation in idle. I was the one who found this and reported it. Don't use the 3 or 4 bar on that ecu. Stock or AEM is fine.