On mine, (full 3" DP and cat back w/dump, custom intake w/Apexi filter, FFIM, 2.5 IC pipes, large real-SPEARCO core bar and plate IC, stock rebuilt CT26 w/NO boost controller, NO shimming of the WG, [see my build for details]) I'm hitting between 10-11 psi. So you can see more than "slight", but...