What do you want to do? These questions are not very specific. Machine accuracy, resolution, cutter deflection, ambient air temperature, rigidity, material, feedrate, etc., etc., all affect the accuracy of the part.
Bridgeports are usually 2 HP not 3 HP (older ones are 1 1/2). What are you doing that you need "3hp worth of performance" (and what does that even mean)?
A standard Series I Bridgeport weighs about 2000 lbs. A Series I Bridgeport CNC (with BOSS control) weighs about 3000 lbs. The CNC is available with a rigid ram. What machine are you talking about?
The task at hand and budget will define the machine you need - what is the task at hand?