left side of throttle body (gearbox side) there is round plug in cast, there are a few vacuum tubes coming from it. Use one of them.
Don't use MAP line, fuel pressure line or 4th throttle line.
Well i wouldnt really buy one myself but one came in the car i bought and it actually tells you how economically your car is driving, like how heavy on juice it is depending on how you drive it lets you know if you are driving easy or not and so on. Its easily explaingd if you can see a good one.