I've been doing almost all my running in Asics Piranhas for some years now. For those who don't know, it's a 4.2 oz racing flat with 4mm heel-to-toe drop. Except my calves my feet have been just fine.
I'm planning to run a marathon in mid-september. Do you think I can/should run it in Piranhas or should I afford something more of a shoe? I've been thinking of Asics hyperspeed 6 (5.6 oz, 6mm drop) or Nike Zoom streak 5 or 4 (6.7 oz, 12 mm drop).
Recommendations?