When I was talking with Renntech about their ECU & pulley upgrade I asked them how much boost I would gain. They told me that the stock SRT6 at around 5,800 to 6,000 RPM the boost was 16 to 17 PSI, and with their kit at the same RPM's the boost would be around 21 to 22 PSI. I found this hard to believe at the time, but in another thread several months ago before I bought and installed the Renntech kit somebody that sounded like they knew what they were talking about said that in their opinion those numbers were true.