This question depends on your engine size and setup, but in general bigger isn’t always better. The goal of a bored throttle body is to increase the smallest part of the throttle body, which increases the potential total CFM. The problem with this is that it will reduce air velocity which can hurt power if your engine isn’t capable of flowing that much air.
A ported throttle body is intended to optimize air flow and promote air velocity which will provide benefits on any engine, but if the throttle body is too small, it will still be a choke point.
You can use this simple formula from High Performance Math to determine an optimal size and compare to your current throttle body.
Or, just visit their site here to use their calculators to make it easy on you.
Do they make the same power?
Yes and also no. If the throttle body is not a choke point, then a ported throttle body will ultimately be a better option because it optimizes air flow without sacrificing velocity. The biggest benefit of a ported throttle body over a bored throttle body is the support for low-mid range power gains.
If the throttle body is a choke point (too small for the engine), then a bored throttle body will end up making more power.
Be careful when you have a shop do work!
Not all shops will perform a full bore! Even if they say they do, most shops perform a port job, and will not touch the throat area because it requires making a new throttle blade and it’s a lot of extra work. Ask the shop before you place your order if they will be making a new blade. If they say no, then they aren’t really boring out the throttle body, but instead doing a port job.