After reviewing the GM Cadillac XLR repair manual the only difference between 2006 & 2008 exhaust system is intermediate pipe hanger PN# 1579005 (2006) and PN# 15784473 / 4 for the (2008). So the CORSA 14156 will fit all XLR's from 2004-08. Am I missing anything else? This is an upgrade I'll do once I find the right price on the CORSA!