Getting usable vacuum with an Individual Runner intake is a little more involved, but certainly not overly impossible.
Wayne used to carry a manifold that had a large open plenum on the bottom. That works really well. He doesn't carry that anymore, and tells me it's no longer available. That's too bad. If you're really lucky, you might find one in the used market.
Otherwise, you'll have to make a plenum. This one was built for me by a company that's no longer around. But it's pretty simple.
For a power brake booster, I would also use a large reservoir on the firewall or underneath the fender.
The actual vacuum signal will depend on how the rest of the engine is built - particularly the cam selection. I have a huge cam and high compression, I don't get much of a vacuum signal at low rpm's.
As for driving experience - it is awesome! Crisp throttle, and power everywhere. EFI is not subject to the same low rpm problems that a carb is. Driving down the highway at 2,000 rpm's is smooth and quiet - sedate as a kitten. But mash the throttle, and it screams like a banshee and takes off like a rocket.
Be aware that any IR system can be difficult to set up and tune; just like any multi-carb intake is. The learning curve is a little bit steep. But once you get it figured out, it's relatively easy. Keep in mind that "Close Enough", isn't.