I was looking at some armani suits very similar to this one a few weeks ago in Vegas, and I seem to remember that the pinstripes coming down the front of the shoulders matched up perfectly with the pinstripes on the front of the sleeves. The suit for sale on eBay has the pinstripes mismatched pretty badly....a second maybe???
Were you looking at Emporio Armani, or Armani Collezioni, or Armani Black label? EA is much cheaper and construction follows suit (no pun intended). I think it's authentic but it doesn't look like it's so great of a deal. You're looking at 50-65% off this suit (assuming that the bidding goes up more), which is typical
for eBay, but not a really amazing deal or anything.