Serious runners know the lighter the shoe, the better. PUMA's L.I.F.T. Racer, which goes on sale this weekend in PUMA Concept Stores nationwide and at store.puma.com starting tomorrow, took this credo to heart, er, sole. The L.I.F.T. Racer is created from lightweight foam injected into a mold, forming its upper in one piece, so there's no gluing, no stitching and, most importantly, no excess weight. But, the price may be the most impressive feature; $75 fits snugly into any recession budget.