best aftermarket boost gauge

[robert weinberg]

i'm ready to install a decent boost gauge in my car being the digital one is dead. and being it's not all that reliable and only reads to 2 bar - it makes for sense to install a good aftermarket one.

i was thinking the autometer 3303. it reads up to 30 psi. i'm running an IA3+. i think it's 2.5 bar - but you deduct 1 bar (14.5 psi) for atmostphereic pressure - being it's NOT manifold (boost)  presure. so, the IA3+ is 21.5 psi, correct? 

so, will a 30 psi boost gauge be fine or will the boost gauge also read atmospheric pressure on top of the manifold pressure?

what i want is to accurately read manifold pressure and have "more gauge" available to keep an eye on overboost.

lastly, some say the IA3+ overboosts to 3 bar (29 psi manifold pressure) - but i've also read it reduces boost at redline to save the turbo.

thanks,
Robby