It doesn't make much of a difference depending on how much restriction is imposed by the factory intake. But its a heck of a rewarding project and the sound is pretty awesome
I had plenty of room under my hood so I just did it with some 3" PVC tubing and an elbow along with some rubber drain pipe joints from Home Depot. For a while I used a chrome big-bore exhaust tip for the tubing but I couldn't get it to seal to the PVC well enough.
If you have a tight engine bay you can get a little more creative. You can maybe find some of that bendable exhaust pipe repair stuff and bend it how you want it, then take it to an exhaust shop and have them bend a piece of applicable exhaust tubing to that shape. You can also buy some pre-made bends of exhaust tubing and weld up your own.
Get creative. You can't go too big so when in doubt go one size bigger than any stock diameters you find.
For the most part you want your intake sensors in about the same location, but don't get anal about it. Within a couple inches should be fine.