my 05 rex is bone stock and i was wondering what gains i could get by getting a Boost controller and upping the boost? (i think stock comes at 14.5psi and jdm rexs run like 17psi? someone correct me here cause im pretty sure im off)

also would this require me to get a boost gauge?

 

before increasing the stock boost, you should look into getting a full exhaust, maybe some injectors and fuel pump. An accurate boost gauge and EGT gauge will help you see how much boost you're actually running and how hot the exhaust gases get. After that, you can easily push about 16 psi with a boost controller. however, what i strongly suggest is, you bring your car to a tuner, and have the tuner play with everything, so that you don't blow your own engine.

 

Hm on a stock turbo would you think upgraded injectors and a new fuel pump are really necessary? I've heard of a lot of people adding 1-2 psi without them, so I'm nto sure. And YES! get a boost gague definitely. EGT isn't a bad idea at all either.
Also, it might be a good idea to look into reflashed ECUs instead of a boost controller. They're safer and maybe more bang for the buck.