Can 20 inch rims fit on a 1994 cadillac concourse you have 16 inch rims on it now do you need an install kit to switch them or can you just switch them as is?

Good luck on this one, but know this, when you change the diameter that much, your speedometer will be off by a lot. The speedometer is geared for a certain diameter wheel/tire combination, and when that gets too big or too small, the speedo doesn't know what to do--