I have a V1 with 3.125 pulley, stock ECU, stock MAF, and stock injectors. Once I add the 370's, Z32 MAF, and JWT ECU how different will my car run? Will there be an increase in power?

 

It will have to capacity to be over 300whp but that depends on the tune from jwt. Their tunes are conservative so don't expect too much.

 

Not sure if it will feel too much different.
Like maxgtr2000 stated, it depends on the tune but since JWT is known for being real conservative if they pull too much timing and make it too rich it could feel a bit more slower but JWT will consider it a "safer" tune.