1.) Hold onto your $1,600 for now
2.) Run bitcoin price calculator to determine exactly how much bitcoin you would mine if you had hardware in hand today.
3.) Wait 3-4 weeks and re-run your calculations for mining coin at same hashrate
4.) And if steps 2 and 3 don't convince you, then jump back onto e-bay in 3-4 weeks and see how much that $1,600 unit is selling for at that time.
If you execute these steps and still decide that putting your $1,600 into mining equipment is smarter than simply purchasing and holding bitcoin then have at it :p