[gap]

08 135i 61,000 miles. 6 months ago I installed Wagner Evo 1 Comp IC,
ER sports oil cooler, ER charge pipe, P3 gauge, and JB+ set at default. Recently added
Maddad mipipes but running stock down pipes. Jb+ set at default which
should add 2.75 psi to the 8.8 max stock boost for a total of around 11.5 psi. Max boost on the P3 shows 9.5 psi. Thought maybe it was the stock DV's leaking so just installed the forge DV's. Tried green springs (5-15 psi ) first then yellow (15-23 psi) with no difference. So....
Is the P3 gauge accurate or just close?
Would it be better to swap back to the green springs?
Is there another reason that it appears 2 psi less than expected.

I know there are a lot of good tunes out there but I'm happy with the JB+ modest gains.