boost drop

[talongod]

I have a 97 tsi w/ intake, 3" exhaust, 1g bov, uicp and mbc my boost guage when floored reads 15 and then drops to like 12 and stays i tried the intake pressure leak test and i found no leaks what can this be?

 

[clownface]

On the stock t-25 the boost falls off a few psi in the higher RPMs like around 6k. That might be whats going on.