Can anyone give me some help on installing a rear bumper add on for my son's Avenger?  The piece attaches to the stock rear bumper.  I know it screws to the wheel well but what is recommended to attach to the bumper?  I've heard double sided tape, liquid nails, a product called fusion.  Any help would be appreciated.

Any of those methods can work ....
Liquid nails if it oozes out can bleed thru the paint at a latter date

Fuzor is a great way to attach it ,yes it's pricey but well worth it

3M moulding tape is also good

Almost any body supply house will have it ... Dunno of a nationwide chain ...Look in the yellow pages