Billionaire activist investor Carl Icahn disclosed a new 12.1 percent stake in The Pep Boys - Manny Moe & Jack and said the auto parts and maintenance chain's retail business should be acquired by Auto Plus - a competitor he controls. Icahn believes Pep Boys' "retail automotive parts segment presents an excellent synergistic acquisition opportunity for Auto Plus, a leading automotive aftermarket company wholly owned by" Icahn Enterprises LP, according to a 13D regulatory filing Friday.