Someone may jump in here and correct me.
My understanding (verified by some quick Googling, for whatever that's worth) is that the MAP sensors measure (duh) absolute pressure, unlike your boost gauge which is measuring relative pressure.
Since the MAP needs to measure vacuum as well as boost, a low (zeroish) output is going to indicate vacuum, while high outputs indicate boost. With the car on and the engine off, I'd expect to see a MAP value that's around 1/3rd of its max output voltage. That would indicate 1 bar (~14.5psi). 3 bar is 43.5 psi, which would correspond to the max sensor output voltage. (I think this is about +5V, but I haven't checked.)
The practical upshot is that 25psi of boost is about 39.5 absolute pressure, or around 2.8 bar. (And, your boost gauge doesn't have the greatest resolution, so 25 could be, say, 25.5.) I read somewhere that the 3 bar MAP sensors actually only read up to around 2.8 bar. In that case, 25psi is very close to the max value that the sensor can accurately read.
TL;DR: Boost above 25psi may not be detectable by the 3 bar MAP sensors.
Blue-ish 2006 2.4, Werks stage 1 turbo, Borla cat-back, DDM braces, Spec aluminum flywheel, Spec stage 2 clutch, Werks aluminum radiator, some gauges, RKSport hood, Morimoto FX-Rs, GReddy Profec, Norm's fenders
'07 GXP, RPM Stage 2, Solocatless downpipe, TCE Wilwood 6 piston front brakes, 4-piston rears , Stainless brake lines, slotted/drilled rotors, BC Racing BR coilovers, Performance Autowerks intercooler, DDMWorks CAI, charge pipes and braces