from all of my sampling you really need 22 inches or 24 inches to really hide them. The main reason for this is if you make the tips level with the ground they dont have to be as long.... but they look bad since the rear bumper angle makes the level tips look pointed down (bad look)
If you angle them up you need a bit more tip. Another thing is do not go with 3 inch tips, stick to 2.75" looks better when you dont have cut out holes for the tips to sit in.
__________________ 2003 Cobra Vert (Redfire) #3938 of 5082 @ 05/27/2003
472rwhp/493rwtq -Modification List - Dyno Sheet 2012 Mustang 3.7L M6 (Kona Blue) 2011 Ford Edge Sport (Red Metallic)