From what my friends have told me they said it helped with the mid-high range. I've yet to have 1st hand experience because I'm in the same situation as you are (is it really worth the 350(new)/175(JG bored+exchange). I think my money is better spent somewhere else...

Going with the option of getting your stock one bored out is probably worth it but I won't be able to deal with not having a car for the 1-2 weeks it takes to get it back from the machine shop. And buying a used one from someone will be costly too [used one 100~ + 175(JG bored+exchange)].

Now finding someone who already has a used bored out throttle body might be the best option but you have to consider the risks. Why are they selling it, do you trust the person they got it bored from, the list goes on.